The fourth season of 'Only Murders in the Building' continues to unravel as Charles, Mabel, and Oliver find themselves in greater danger, realizing they are now targets of a killer. After escaping to Charles' sister Doreen's home in Long Island, they receive threatening texts, prompting a deeper investigation alongside actors portraying them in a movie about their podcast. Episode 7 reveals shocking connections to past seasons, suggesting that a killer has remained at large since Season 1 and that previous suspects may have been misidentified. The trio’s latest findings tie back to their first season, revealing that the killer's presence has been more pervasive than anticipated. The episode also showcases character developments and reunions, particularly between Charles and his estranged sister, enriching the storyline amidst the ongoing murder mystery. With new clues and celebrity insights, the narrative promises to shift perspectives on the intricate web of deception they've been unraveling.