After Sal's plan to trick Dana into thinking he's become a real baby works, they start enjoying a happy and playful life. However, things start to get complicated when Dana discovers that her hormonal serum has unexpected side effects. Sal begins to regress into an infant-like state and loses control over his bladder and other bodily functions.
Despite his initial excitement about being taken care of by his wife, Sal soon realizes the seriousness of his situation. As he becomes more and more dependent on Dana, she begins to feel overwhelmed and exhausted by the constant care needed to attend to an adult baby.
As they struggle to find a cure, Sal and Dana's relationship takes a bumpy ride. Sal feels frustrated and alone, while Dana is torn between her love for her husband and the weight of her scientific discovery. In the end, they both discover the importance of growing up and learning to take responsibility for their own lives and choices.
Manbaby is a hilarious and heartwarming comedy that explores the absurdity of adulthood and the unpredictable nature of love and relationships.