In season four, Charles, Oliver & Mabel wrestle with the shocking events at the end of season three surrounding Charles's stunt double & friend Sazz Pataki. Questioning whether Sazz or Charles was the intended victim, our trio's investigation leads them all the way to Los Angeles where a Hollywood studio is readying a film about the Only Murders podcast. As our amateur sleuths race back to New York, they embark on an even more epic journey - traversing their building's courtyard to delve into the twisted lives of the Arconia's West Tower residents.

Following the death of a leading man on opening night of Putnam`s new show, it appears that the killer is someone involved in the show, so the Only Murders team starts to dig into the show's cast of theater actors with big personalities and potentially even bigger secrets to figure out who is the murderer among them.