In the season premiere, the staff must relocate to an American Army base in Japan. STEVE AGEE (Jimmy Kimmel Live), JON HAMM (Mad Men) and KEEGAN MICHAEL KEY (MADtv) guest star.

When the son of Nurse Dori (ZANDY HARTIG) witnesses a murder, Detective Chance Briggs (NICK OFFERMAN) arrives to solve the crime ... but he doesn't count on falling in love.

A night of entertainment on the base is threatened by a plane crash -- until a survivor offers help. Also, Owen doesn't get stuck in a time loop.

The day has come for Cat and Michael's (JUSTIN KIRK - Weeds) nuptials. The doctors gather at Cat's vacation house, until two shocking events threaten to dampen the celebration.

The doctors fight to save the hospital ward that houses ailing imaginary friends ... and also has great cell reception. BRIAN DOYLE-MURRAY, JAY JOHNSTON guest star.

Lola is recruited by an elite, secret government task force, but a ghost from her past threatens to compromise her mission. Recurring guest star JORDAN PEELE (MADtv, Key and Peele) appears.

Sy's plan for a costumed theme day on the base becomes more complicated than expected. BETH DOVER, JAMES URBANIAK and STEVEN WEBER guest star.

To get rid of Owen's perm, the doctors hatch a plan involving a haunted house and Omni magazine. Meanwhile, Blake learns how Glenn is so good at surgery.

A famous Army hospital critic visits the base on the same day as a scheduled wine tasting. WILLIAM ATHERTON (Die Hard) guest stars.

Blake's abduction presents Owen with a chance to boost ratings on his medical talk show.

Derek Childrens vows to regain control of the hospital from Sy. Guest stars include JON HAMM (Mad Men), JOHN GEMBERLING (The Heart, She Holler) and IAN ROBERTS (Reno 911!).

DAVID WAIN's personal documentary about his lifelong friendship/rivalry with Childrens Hospital cast member Just Falcon. KERRI KENNEY (Reno 911!), SAM TRAMMEL (True Blood) appear.

The doctors' trip to Japan comes to a shocking climax involving birth, death, sex, war and opera. Guest stars include JACK McBRAYER (30 Rock) and DAVID WAIN.