Dr. Danny Maccabee, portrayed with a delightful mix of humor and sincerity by Adam Sandler, has been nursing a wounded heart ever since his wedding day was marred by the painful discovery of his bride's betrayal. In an attempt to shield himself from genuine relationships and assert control in his life, Danny crafts the identity of a lovelorn husband seeking brief romantic escapades. This carefully curated facade, however, begins to crack when he meets Katherine Murphy, played by Jennifer Aniston, a pragmatic office manager with an inherent kindness who quickly recognizes his deception.
In an unexpected twist of fate, Danny encounters Palmer, a vibrant and unsuspecting young teacher, at a beach gathering. Their light-hearted interaction comes to an abrupt halt when Palmer spots the wedding ring on Danny's finger, leading her to exit in haste. Rather than come clean about his lies, Danny fabricates a complex story involving a cheating ex-wife named Devlin and a legendary accomplice, intriguingly dubbed Dolph Lundgren. Subsequently, Katherine becomes entangled in this intricate charade, reluctantly stepping in as Devlin to grant her covert approval to Palmer.
As the plot thickens, Palmer's instincts tell her that something crucial is amiss. She demands to meet Michael and Maggie, who, unbeknownst to her, are actually Katherine's kids. The hilarious ruse escalates as Eddie, Danny's cousin and former "Dolph Lundgren" impersonator, arrives unexpectedly at the airport, compelling the group to concoct new alibis on the spot.
Their escapades eventually lead them to the sun-drenched beaches of Hawaii, where they encounter Devlin Adams, a clever socialite, and her husband Ian. As Katherine's feelings for Danny deepen, she finds herself in a profound dilemma—torn between her loyalty to her friend Devlin and her growing affection for the unrepentant womanizer. Meanwhile, Palmer surprises everyone with her proposal to marry Danny, causing him to reassess his views on love and commitment.
As the night unfolds, Palmer ventures into delicate territory when she brings up Katherine's unaddressed feelings for Danny, only to be met with a sharp rebuttal. In a twist of fate, Katherine reconnects with Devlin at a local bar, where she candidly shares her ploy of feigning a marriage to sidestep potential awkwardness with Danny. Devlin, in turn, reveals her plans to divorce Ian, who is grappling with his own identity.
In this moment of honesty, Katherine confesses the profound nature of her feelings for Danny, just as he unexpectedly enters the scene. With a revelation that will dramatically alter their lives, Danny admits that he cannot proceed with marrying Palmer because his heart rightfully belongs to Katherine. This leads to a fervent kiss, solidifying their undeniable bond.
As the tangled threads of attraction continue to unravel, Palmer discovers new comfort in an unexpected romance with a professional tennis player who shares her interests. Meanwhile, Danny and Katherine make a pivotal decision about their future together as they plan to wed, signaling the start of an exciting new chapter in their lives.
