Nick Kroll is not funny. Unfortunately, this is not the primary tragedy of “Adult Beginners.”  In director Ross Katz’s second feature, Kroll, of “Kroll Show” notoriety, plays a serious role. Not only is it hard to take him seriously—it is hard to care. Without his “Kroll Show” personas, Nick just is not a very interesting guy. What is more, the lack of inspiration in the film’s screenplay amplifies the overbearing blandness of the film’s leading man. Tired clichés alternate with jokes that fall flat, and the sleep-inducing result is a sort of Judd Apatow knock-off—a quirky family buddy movie stripped of all the humor and talent.

The backstory requires little explanation, as it is clear that the writers gave it little thought. The details are irrelevant: The audience is simply meant to understand that Jake (Kroll) is on top. He lives in a swanky Manhattan apartment, rubs shoulders with wealthy, suit-clad white guys, and makes out with pretty blondes in marble bathtubs. Due to a poor investment decision, however, he abruptly loses everything. One emotional train ride later, Jake is on the doorstep of his sister, Justine (Rose Byrne). Justine, a busy mother who teaches at a local school, allows Jake to stay with her on the condition that he babysit her son, Teddy (Caleb and Matthew Poddack), during the day. This is an arrangement that is sure to kill a whole flock of seagulls with just one stone: Justine and her husband Danny (Bobby Cannavale) save money on daycare, Jake gets a place to stay, and—most importantly—Jake gets the dose of reality he so sorely needs.

Unfortunately, reality has its problems, too. Behind the innocent picket fences of Justine’s neighborhood lies an Updikean web of adultery, deception, and regret. And yet, the writers dig no deeper into this web than the commuter belt clichés. They hit all the midlife crisis film tropes but fail to develop the beyond their barest form. Still, admirable performances by Byrne and Cannavale salvage their otherwise dull setting. Byrne, for her part, manages to be both poignant and funny. She is relatable as a mother who has stretched herself too thin, and she delivers her exhausted musings convincingly. Cannavale is an oafish contractor whose amiable, boyish demeanor provides a refreshing complement to those of the more serious characters in the film. Byrne and Cannavale do the “cool couple” shtick very well, and, even if their marriage is deadly close to falling apart, one cannot shake the feeling that they would make great guests at a neighborhood barbecue.

Kroll’s character, however, possesses few redemptive qualities. From the beginning of the film until the final minutes, Jake is a jerk. He is not a jerk who is secretly likeable or a jerk who is misunderstood; he genuinely just does not have any positive qualities. His selfishness is what drives him into his rut, and this selfishness continues when he moves in with his sister. Moreover, Kroll plays the character with such malaise that it is difficult to believe that Jake ever had any success in the first place.

The film’s title comes from a swim class that Jake and Justine take with Teddy during the film. Never taught how to swim by his emotionally neglectful parents, Jake is offered a spot in the adult beginners course. The course is probably a lazy metaphor for his inability to act like a real adult, and Jake refuses it. But in the film’s climax, when swim instructor Miss Jenn (Jane Krakowski) informs Jake and Justine that Teddy will not jump in the water unless they do so first, the two must conquer their fears and take the plunge. As rhey submerge their heads in the water and the adorable Teddy joins them, they finally make one big happy family.

This is sweet. Sweet like a shot of crude oil saturated with Splenda. With so many deep-seated problems in this family, it seems dubious to suggest that this group baptism will cleanse them of their sins, but the light-hearted music that accompanies the credit reel seems to suggest just that. Like its peer films, “Adult Beginners” takes a whole lot of family clichés, stirs the pot with a contrived crisis, and serves the product neatly on a platter in under 90 minutes. What makes the film exceptional in its class is that it is not even fun. What few drops of enjoyment may have existed in this script prior to shooting are sucked out by Kroll’s vampiric lethargy, and all that remains is the film’s lifeless corpse.