Thirty-year-old botanist Peter Reynolds is painfully shy, socially awkward, and seemingly destined to remain a bachelor forever. Despite his professional success studying rare flora, his personal life is completely stagnant. He suffers from a rare endocrine disorder that prevented him through no fault of his own from experiencing typical puberty, leaving him physically and emotionally stunted. His overbearing parents coddled him, and his best friends, eager to see him finally live a full life, constantly push him out of his
comfort zone, particularly regarding his long-standing, unrequited crush on his gorgeous neighbor, Michelle.Everything changes when Peter visits a specialist who discovers a benign pituitary tumor restricting his hormones. The doctor recommends an aggressive, immediate treatment plan to finally jumpstart Peter's biology. Within days, the therapy takes effect, and Peter’s body undergoes a chaotic, overnight
transformation. He rapidly develops a mature physique, deepens his voice, and experiences an overwhelming surge of testosterone that sends his libido into overdrive.Initially, Peter is thrilled by his newfound vitality and physical attractiveness, but the sudden rush of hormones wreaks havoc on his daily life and emotional stability. He struggles to control his intense sexual impulses, leading to a series of hilarious yet awkward social missteps at his botanical laboratory and out in public. His sudden transformation also complicates his relationship with Michelle. Once invisible to her, Peter is now suddenly the object of her attention, yet his clumsy, hormone-driven advances create tension between them.As the testosterone overload peaks, Peter realizes that physical maturity is only half the battle; he still lacks the emotional maturity to handle his new reality. He alienates his worried parents, frustrates his supportive friends, and jeopardizes his budding romance with Michelle by acting rashly and selfishly. A humbling wake-up call forces him to take a step back and balance his newfound physical drives with genuine emotional connection.Ultimately, Peter learns to master his impulses and apologizes to those he hurt. He proves to Michelle that beneath the sudden physical changes, he is still the kind, thoughtful botanist she always knew, just finally equipped to handle a real adult relationship. The film concludes with Peter fully embracing his adulthood, confident in his own skin, and happily embarking on a passionate romantic future with Michelle.