Matt Sullivan, a young web designer in San Francisco, finds himself heartbroken after a painful breakup. Struggling to move forward, he becomes obsessed with his ex-girlfriend and their past relationship, leading him to a cycle of meaningless encounters. In an attempt to regain control over his life and his sexual urges, Matt takes a vow of celibacy for the 40 days and 40 nights of Lent. He sees this extreme pledge as a means to purify his mind and soul, hoping it will help him to find a new beginning and maybe even true love.

As Matt embarks on his journey of self-restraint, his commitment is immediately tested by friends, co-workers, and even strangers, who find his vow amusing and challenge it in every possible way. His life becomes increasingly complicated when he meets Erica, a captivating woman who embodies everything he desires. As they grow closer, Matt must navigate the complexities of starting a new relationship while strictly adhering to his pledge. His resolve is pushed to the limit, forcing him to confront what he truly wants in love, life, and the possibility of a future with Erica.