“Only Murders in the Building,” the mystery surrounding the murder of actor Ben Glenroy (played by Paul Rudd) takes center stage. At the end of Season 2, the audience witnessed Ben’s murder, leaving fans on a suspenseful cliffhanger. As Season 3 unfolds, it is revealed that Ben miraculously survived the poisoning attempt meant to kill him. He apologizes for his previous arrogant behavior but is later found dead again, this time in the elevator of Mabel (Selena Gomez), Charles (Steve Martin), and Oliver’s (Martin Short) apartment building.

The suspects are numerous, including cast members of the Broadway play in which Ben was involved, such as Loretta Durkin (Meryl Streep), Ben’s brother Dickie (Jeremy Shamos), and Charles’ girlfriend Joy (Andrea Martin). Mabel and Charles follow various leads, including a tissue found in Ben’s hand and a camera recording of his final hours. A devoted fan is arrested for suspicion of murder, but Mabel doubts his guilt.
Meanwhile, Oliver becomes suspicious of Loretta, with whom he has developed a closer relationship. It is eventually revealed that Dickie, Ben’s brother and manager, is Loretta’s son, and she is willing to protect him at any cost. The truth behind the murder is unveiled when it is discovered that producer Donna (Linda Emond) poisoned a cookie that Ben consumed before his performance, aiming to sabotage him due to a scathing pre-review of the play. Donna’s motive was to save her son Cliff’s (Wesley Taylor) Broadway career.
However, the story takes another turn when it is revealed that Ben survived the poisoning attempt but was later pushed down the elevator shaft. Donna admits to this act, but Mabel suspects there is more to the story. Confronted backstage, Cliff confesses to pushing Ben after an argument where Ben threatened to report Donna to the police for the poisoning attempt.
In the midst of the chaotic play’s performance, Oliver confronts Cliff with his theory, leading to Cliff’s confession. Cliff attempts suicide but is stopped by his mother. The season concludes with a shocking event at the Aftershow party, where Charles narrowly escapes an attempt on his life. However, it is Charles’ longtime stunt double, Sazz (Jane Lynch), who gets shot and leaves a cryptic message with her own blood before dying.
This gripping finale leaves viewers on another cliffhanger, setting the stage for a new mystery to unravel in Season 4.