Jeff Chang is a straight-laced college student who always meets high expectations. On the night of his 21st birthday, his best friends from childhood, Casey and Miller, surprise him with a visit, intending to celebrate the milestone in proper legal-drinking-age style. Despite an important medical school interview the following morning, Jeff succumbs to pressure and decides to go out for a single drink with his friends. However, what starts as a quick celebration spirals into an out-of-control night of partying and debauchery.

As the night progresses, the trio's plans derail spectacularly. The one-drink promise fades in the rearview as they encounter bar hopping, chaos, and unforeseen encounters that test their friendship and future. They navigate their way through the wild college party scene, and as Jeff's interview looms, the simple task of getting him home and sober becomes an increasingly difficult feat, with each bizarre turn complicating their mission even further.