Martha, a heartbroken woman reeling from a recent breakup, unexpectedly crosses paths with the charismatic and eccentric Francis. Under his charming exterior, Francis happens to be a professional assassin with a peculiar moral code: he only kills those who hire him to kill others. Their connection is instant and magnetic, leading them to a whirlwind romance filled with dance-offs and quirky adventures. However, Martha's new beau didn’t entirely abandon his old life, and his lethal career soon begins to interfere with their burgeoning relationship, forcing Martha to confront uncomfortable truths about her lover.

As Martha grows closer to Francis, she inadvertently becomes entangled in his dangerous world. Various assassins and adversaries come out of the woodwork, complicated by the involvement of an enigmatic and persistent government agent tracking Francis's every move. The balance of their affection and the chaotic underworld tests their relationship, making Martha question whether she can truly handle the unconventional life Francis leads. The story builds up steadily with splendid comedic timing and action sequences until everything culminates in an exciting showdown where love, loyalty, and survival hang in the balance.