"Happy Anniversary" follows a devoted Latino couple, Aaron and Serena, as they embark on a weekend getaway to celebrate their milestone anniversary at a charming vacation cabin. After settling in, they unexpectedly encounter Brian, their friendly "Vacay" host. Despite Aaron's growing unease due to Brian's frequent "accidental" intrusions, Serena dismisses his concerns as mere coincidences. As the evening unfolds, Aaron plans a beautifully romantic surprise for their anniversary before heading out for dinner. However, a shocking twist reveals that Serena has been drugged, not by the expected perpetrator. When she awakens, she finds herself bound and held captive. Aaron exposes evidence of her ongoing misconstrued betrayal and refuses to entertain her excuses. As he intends to follow the vows of their marriage, "till death do us part," he meets an untimely demise at the hands of an unexpected savior-Brian.