Max implements sweeping changes to hospital sustainability practices; Bloom returns from vacation, surprising everyone with a new attitude; Iggy discovers a dangerous situation with a former patient.

When Beckett and her team burst into an apartment on a murderer's trail, they see Castle standing over a dead woman's body holding a gun; Beckett arrests Castle as he asserts his innocence.

A nasty flu season is masking a terribly infectious disease; Chastain must race to quarantine and diagnose infected patients; Devon treats a lovesick patient who has flu-like symptoms; Conrad doubts whether Nic is prepared to take the next step.

Patrick Jane tries to prove a man carrying a gun at a political rally is planning to commit murder; Lisbon looks into a photographer's death.

When Agent Susan Darcy asks Jane for help with an investigation, he suspects her motives; the team handles the murder of a woman who was killed after meeting someone in a chat room.