• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Michael Rady (Evan Murphy), Lisa O'Hare (Kitty Canary), Charlene Amoia (Ana Marie), Gino Cafarelli (Dean Carbino), Ethan Erickson (Xander Foyle)
• Co-Starring: Craig Gellis (Earl), Justice Gamble (Bartender), L.T. Tolliver (Uniform Officer)
• Written By: Andrew W. Marlowe
• Directed By: Rob Bowman

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Bess Armstrong (Paula Casillas), Rachel Boston (Penny Marchand), Mercedes Masöhn (Marina Casillas), Bre Blair (Toni Johnston), Rick Ravanello (Steve Adams), David Gianopoulos (Albert Moreno), Evan Helmuth (Nick Johnston), Kieren Hutchison (Cody Donnelly)
• Co-Starring: Paige Rowland (Loreen Carter)
• Written By: Moira Kirland
• Directed By: John Terlesky

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Jason Beghe (Mike Royce), Keith Robinson (Random Pierce), Sophina Brown (Gayle Carver), James Handy (Clifford Stuckey), Brian Krause (Father Arron Roe)
• Written By: Alexi Hawley
• Directed By: Bryan Spicer

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Andrew Harrison Leeds (Adam Murphy), Ian Nelson (Troy Kenworth), Ken Baumann (Ashley), Victor Webster (Josh Davidson), Muse Watson (Ivan Podofski), Thomas Kopache (Abe Sandrich), Jim Piddock (Henry), Ramón De Ocampo (Owen Peterson), Randal Reeder (Roland D'Andre), Eden Riegel (Rachel Goldstein)
• Co-Starring: Jen Lilley (Julia Foster), Eugene Shaw (Joe)
• Written By: David Grae
• Directed By: Rob Bowman

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Michael Cassidy (Greg McClintock), Monet Mazur (Gina Griffin), A Martinez (Cesar Calderon), Carlos Sanz (Manuel Calderon), William Allen Young (Jerry Camden), Bo Foxworth (Leonard Maloney), John Kassir (Mr. Dreyfus)
• Co-Starring: Nathan Lam (Rabbi), Erin Fleming (Amy Porter), Cynthia Frost (Tova), Brea Cola (Dr. Imani Phelps), Allyssa Maurice (Dr. Lissa Ackerman)
• Written By: Terence Paul Winter
• Directed By: John Terlesky

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Lee Tergesen (Marcus Gates), Michael Mosley (Jerry Tyson), Brian Klugman (Paul McCardle), Anne Marie Howard (Angela Russo), Joe O'Connor (Cal Townsend)
• Co-Starring: Ping Wu (Dr. Lee)
• Written By: David Amann
• Directed By: Bill Roe

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Mary Page Keller (Rebecca Dalton), Samantha Quan (Kathleen Park), Christina Vidal (Jamie Ruiz), Philip Anthony-Rodriguez (Michael Grant), Gideon Emery (Lloyd Saunders), Blake Gibbons (Billy Grimm), David Barry Gray (Bert Kramer), Adriana DeMeo (Bella Lombardo), Clint Glenn (Hans Von Mannschaft), Austin Highsmith (Camille Roberts)
• Co-Starring: Corey Saunders (Derek Brookner), Kelsey Gunn (Sarah Lieberman), Sam Doumit (Mandy Carson), Leandro Cano (Bouncer), Dana Ward (Sexy Reporter)
• Written By: Elizabeth Davis
• Directed By: Felix Alcala

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: John Pyper-Ferguson (Dean Donegal), Ever Carradine (Mirielle Lefcourt), Ken Baumann (Ashley), Carmen Argenziano (Mario Rivera), Rick Hearst (Dr. Elliot Lefcourt), David Dean Bottrell (Byron H. Singer), Presciliana Esparolini (Teresa De La Torre), Christopher May (Arthur Sansone)
• Co-Starring: Gattlin Griffith (Tyler Donegal), Paul Eric Jerome (Man #1), J. Marvin Campbell (Man #2), Claudia Choi (CSU Photo Technician), Al Pugliese (Pretzel Vendor), Danny Downey (BMX Rider #1), Eddie Fiola (BMX Rider #2)
• Written By: Matt Pyken
• Directed By: Bryan Spicer

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Lance Henrickson (Benny Stryker), Neil Hopkins (Ted Carter), Jeanette Brox (Ayyana Holder), Nicole Bilderback (Joy Harrison)
• And: Lyle Lovett (Agent Westfield)
• Co-Starring: Karl T. Wright (Dr. Chuck Vaughn), James Ellis Lane (Agent Eastman), J. David Krassner (Bob Linden), Jeremy Forte (Security Guard)
• Written By: Shalisha Francis
• Directed By: Bethany Rooney

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Sam Page (Brian Elliott), Chris Mulkey (Wilbur Pittorino), Oliver Muirhead (Steven Heisler), Alexandra Barreto (Annie Swift), Rand Holdren (Pete Mucha), Guy Wilson (Jeffrey McGuigan)
• Co-Starring: Nathaniel Marston (Grant Vyro), Jillian Clare (Gracie), Ritu Lal (Jill), Christopher Carrington (Man), Michelle N. Carter (Woman)
• Written By: Scott Williams
• Directed By: Bryan Spicer

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Thomas Calabro (Scott Donner), Stephen Macht (Bill Wellington), Juliana Dever (Jenny Duffy-O'Malley), Randall Batinkoff (Brad Williams), Tymberlee Hill (Julie Taylor), David Parker (Duke Jones)
• And: Laura Prepon (Natalie Rhodes)
• Co-Starring: Kelly Thiebaud (Chloe Graves), John L. Curtis (Desk Clerk), Jon Briddell (Rich Weiss), René Ashton (Amelia Weiss), Melody Thomas Scott (Tonya Wellington), Lenny Citrano (Lead Lawyer), James Andrew Walsh (Desperate Man), Juan Alfonso (Delivery Man), Schae Harrison (Uniforn Police Officer)
• Written By: David Grae
• Directed By: Jeff Bleckner

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Jeff Hephner (Edmund and Zalman Drake), Brett Cullen (Christian Dahl), Vanessa Lengies (Eliza Winter), Chadwick Boseman (Chuck Russell), Carrie Genzel (Naomi Dahl), Lenny Schmidt (Jerome Aspenall), Adrian Sparks (Thaddeus Magnus)
• And: Gilles Marini (Tobias Strange)
• Co-Starring: Henry Hayashi (Lawyer)
• Written By: Terri Edda Miller
• Directed By: Millicent Shelton

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Max Martini (Hal Lockwood), Brian Goodman (Gary McCallister), Jonathan Adams (Vulcan Simmons), Joel Polis (John Raglan), John Kapelos (Joe Pulgatti), Brian Norris (Chad Rodrick), Chryssie Whitehead (Kathy Moore)
• Co-Starring: Ajay Vidure (CSU Tech)
• Written By: Will Beall
• Directed By: Tom Wright

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Wilmer Calderon (Marvin "Oz" Osminkowski), Alastair Duncan (Reginald Easley), Joe Reegan (Shawn York), Clare Carey (Noreen Hixton), Ned Bellamy (Logan Meech), Brian Michael Jones (Ty Page), Greg Alan Williams (Jim Van-Eps), Josh Wingate (Greg Page), John Hemphill (Tom Walters), J. Salomé Martinez (Todd Shipley), Rachel Melvin (Nicole Hixton)
• Written By: Alexi Hawley
• Directed By: Emile Levisetti

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Jason Wiles (Damian Westlake), Tom Irwin (Simon Campbell), Alicia Coppola (Amber Patinelli), Efrain Figueroa (Ray Salazar), Andrea Bogart (Callie Langston), Ethan Phillips (James Farnham), Jack Dimich (Morris Hasberg), Marlene Forté (Blanca), Michelle Anne Johnson (Officer Greta Bailey)
• Co-Starring: Kareem Grimes (Omar Lincoln), Paul Clausen (Charles Utley)
• Written By: Moira Kirland
• Directed By: John Terlesky

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Adrian Pasdar (Agent Mark Fallon), Bahar Soomekh (Nazihah Alhabi), Lochlyn Munro (Kevin McCann), Alon Moni Aboutboul (Fariq Yusef), Victor Webster (Josh Davidson), Matt Bushell (Leeman Jones), David Weidoff (Craig)
• Co-Starring: Peter Marek (Jamal Alhabi), Billy Mayo (Senior Officer), Hahn Cho (Hazmat Specialist)
• Written By: David Amann
• Directed By: Rob Bowman

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Adrian Pasdar (Agent Mark Fallon), Bahar Soomekh (Nazihah Alhabi), Lochlyn Munro (Kevin McCann), Alon Moni Aboutboul (Fariq Yusef), Victor Webster (Josh Davidson), Monica Kenna (Charlene McCann), Piter Marek (Jamal Alhabi)
• Co-Starring: Jonathan Runyon (DHS Technician), Jeff Denton (Evan Bauer), Billy Mayo (Senior Officer), Benjamin Patterson (Paramedic)
• Written By: Andrew W. Marlowe
• Directed By: Bill Roe

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Corbin Bernsen (Lance Buchanan), Rebecca Budig (Mandy Bronson), Cameron Mathison (Vince Bowers), Tina Majorino (Reese Harlan), David Eigenberg (Peter Connelly), Colleen Foy (Lauren Goldberg), Jodi Taffel (Carrie Albert), James C. Victor (Johnny Dimes)
• And: Jane Seymour (Gloria Chambers)
• Written By: Elizabeth Davis
• Directed By: David M. Barrett

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Bruce Davison (Lou Karnacki), Jay Paulson (Eddie), Kwame Patterson (Wardell Williams), Larry Clarke (Tony Muller), Jeremy Glazer (Nick Keller), Judith Moreland (Sandy Jenkins), Kathleen M. Darcy (Dawn Craig), Michael Maize (Hank Roszell)
• Co-Starring: Ray Stoney (Otis Williams), Tom Virtue (Judge Fitz), Jim Meskimen (Randolph Addison), Houston Rhines (Stephen Addison), Jesse Hlubik (Joe McUsic)
• Written By: Terence Paul Winter
• Directed By: Jeff Bleckner

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Peter Onorati (Sal Malavolta), Gary Basaraba (Ralph Carbone), Gregg Daniel (Walt Shaw), Joe Guzaldo (Luca Sabalini), Darin Brooks (Nick Jr.), Beth Behrs (Ginger)
• And: Liz Vassey (Monica Wyatt)
• Co-Starring: Stephan Smith Collins (Harley), John Ciccolini (Vinnie Delfino), Alton Clemente (Server)
• Written By: Scott Williams
• Directed By: Steve Boyum

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Special Guest Stars: Michael Connelly (Himself), Dennis J. Lehane (Himself)
• Guest Starring: Justin Bruening ("Rocket" Rob Tredwyck), Brendan Hines (Alex Conrad), Erik Palladino (Coach Rome), Andrew Lawrence (Tommy Marcone), Josie Loren (Bridget McManus), Kathleen Mary Carthy (Lorraine Dinovi), Peter Parros (Dr. Raymond Colabro)
• Co-Starring: Ben Bledsoe (Brian Morris), Zoran Radanovich (Jimmy Lennon), Bruce Katzman (Benjamin Morris), Tom Jourden (Lawyer), Roy Huang (Aaron Choi), Kelley Robins Hicks (Julie Singer), Katrina Nelson (Bartender), Crispian Belfrage (Photographer), Yasmine Abriel (Girl)
• Written By: Matt Pyken
• Directed By: Paul Holahan

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Jason George (Charles Kelvin), D.B. Sweeney (Detective Kyle Seeger), Derek Phillips (Reggie Walsh), Jason Beghe (Mike Royce), Gene Simmons (Himself), P.J. Byrne (Tony), Todd Sherry (Maurice), Ransford Doherty (Donald Mannis)
• And: Dominic Purcell (Russell Ganz)
• Co-Starring: Ryan Deal (Actor Ryan), Justice Gamble (Actor Esposito), Julia Voth (Violet Young), Exie Booker (LAPD Officer), Randa Walker (Flight Attendant)
• Written By: Alexi Hawley
• Directed By: John Terlesky

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Michael McKean (Victor Baron), Arye Gross (Medical Examiner Perlmutter), Sasha Roiz (Bobby Stark), Amanda Schull (Joy), Jonathan Slavin (Justin Hankel), Bellamy Young (Candace Ford), Ken Baumann (Ashley), Judith Scott (Evelyn Montgomery), Terrell Clayton (Dax Lattimer), William Francis McGuire (Dan Middleberry)
• And: Teri Polo (Kayla Baron)
• Co-Starring: Krystal Joy Brown (Sasha), Stephanie Lynn (Amber Middleberry), Rosero McCoy (Felix), Nan McNamara (Stage Mother)
• Written By: Terri Edda Miller
• Directed By: Jeff Bleckner

• Starring: Nathan Fillion (Castle), Stana Katic (Kate), Susan Sullivan (Martha), Ruben Santiago-Hudson (Montgomery), Molly Quinn (Alexis), Jon Huertas (Esposito), Tamala Jones (Lanie), Seamus Dever (Ryan)
• Guest Starring: Max Martini (Hal Lockwood), Scott Paulin (Jim Beckett), Brian Goodman (Gary McCallister), Judith Scott (Evelyn Montgomery), Matt McTighe (Chuck Ryker), George Gerdes (Mike Yanavich), Malcolm Foster Smith (Dwight Haskell)
• Co-Starring: Daniele Watts (Rebecca Montgomery), LaNiesha-Jopré Irvin (Mary Montgomery), Sean Blodgett (Avery Zussman), Priscilla Garita (Bridge Officer)
• Written By: Will Beall
• Directed By: Rob Bowman