The primary reason to watch the fifth season of “Only Murders in the Building” is the same one that prompted viewers to tune into the first one: its trio of lead actors. With every episode, Martin Short, Steve Martin, and Selena Gomez comically capture the dynamic of the law of three, with Mr. Short’s Oliver galvanizing and grunting, Mr. Martin’s Charles hesitating and hallucinating, and Ms. Gomez’s Mabel mediating and making sense of it all. 

“It all” constitutes the seasonal solving of a fresh murder case, which also draws one in, though recent seasons have almost cast aside this sleuthing for madcap dives into musical theater and filmmaking. Based on the first three episodes, the latest seems to return to the show’s central Hardy Boys meet Nancy Drew premise, with extracurricular pursuits kept to a minimum. That the murder mystery involves the death of someone actually affiliated with the regal Arconia (the real-life Belnord building on 86th Street) and not tangentially, as in the prior two seasons, only confirms this feeling.

The fourth season ended disturbingly, with the body of doorman Lester (Teddy Coluca) lying in a pool of blood within the fountain in the courtyard, where Oliver had just married actress Loretta (Meryl Streep). The new season’s initial episodes quickly pick up this thread. The three gumshoes/podcasters reject the official determination of an accidental death, and viewers will likely agree based on the evidence, such as a severed finger. This digit leads to some strained physical comedy during Lester’s wake, yet it also points to a connection between the doorman’s demise and another plotline teased last season: the disappearance of pseudo-gangster Nicky Caccimelio (Bobby Cannavale).

In their attempt to link Lester’s death to the missing mobster, Oliver, Charles, and Mabel make for Staten Island and the iconic house where the opening scenes of “The Godfather” were filmed. The Caccimelio family lives within, including Sophia, the seductive matriarch played by Téa Leoni, an elderly Italian nonna, and five boisterous brothers. Offensive Italian stereotypes are mocked just as much as they feel reiterated. 

The second episode reinforces the back-to-basics approach with its tribute to New York City doormen and focus on Lester’s life. Scenes flash back to when a young Lester started out as an apprentice in the 1990s, when a hand-crank elevator was still in use, and to when he became head doorman. Glimpses of our protagonists over the years entertain, while the montage also harkens back to characters from earlier seasons, such as Nathan Lane’s Teddy, hinting at a crime related to prior murders in the building.

The trio’s present-day discovery of a casino underneath the residence, which resembles Grand Central’s Oyster Bar, adds to the season’s New York history-centric vibe. It’s during the third episode, though, that the season really shifts into the show’s high comic absurdity gear. The body of Nicky is found and brought to Charles’s apartment, where the three endeavor to perform an amateur autopsy. The ickiness of this activity is somewhat alleviated by Charles’s visions of the deceased joking with him, much in the same way that humorous tangents throughout the series lighten what is essentially a show about violent homicides. Emphasis on Oliver and Charles’s elevated ages and poetry by Pablo Neruda indicate how the subject of death and dying might be explored with greater depth in future episodes.

Mr. Short continues to provide the series with its biggest laughs as a result of his rollicking delivery and thrashing about, despite the actor’s overuse of nasal and guttural exhortations. Mr. Martin, of course, also supplies amusement and goofiness, but it’s of a more subdued sort, in line with his character’s drier personality. And Ms. Gomez has come a long way from her tentative, almost ineffectual tone in the first few seasons, with the actress/social media maven’s acting exhibiting increasing confidence and demonstrative urgency as the show progressed, fittingly reflecting Mabel’s maturity.

Guest stars remain a hallmark of the show, with Dianne Wiest and Keegan-Michael Key being welcome additions as, respectively, Lester’s widow and the mayor of New York City. The third episode’s final minutes introduce a few more: Christoph Waltz, Renée Zellweger, and Logan Lerman. They play three of the world’s richest people, with voiceover describing their cutthroat business practices as the resumption of tactics often employed by a bygone mafia, strangely forgetting how executives and entrepreneurs of yesteryear also took ruthless tacks.

Take away the obvious “whodunit” red herrings and overwrought, farfetched investigations, and “Only Murders in the Building” works as a situational comedy about two arts-affiliated seniors and a culturally clueless young woman. Indeed, the quirky chemistry between the three actors creates a believable friendship, one that we look forward to watching every week as they deal with their even odder neighbors. That this synergy coincides with a farcical view of New York and the occasional dead body only makes the series more unmissable.