Unlucky in love, chemist Paul Matthews visits gypsy Madame Rosa for help. Quickly realizing he is a hopeless nerd, she gifts him with Love Potion No. 8, which makes anyone who wears it irresistible to the opposite sex for four hours. Paul and animal psychologist coworker Diane Farrow decide to test it on themselves. The awkward pair suddenly find themselves alluring to anyone they approach, but soon realize they are most attracted to each other.
God has had enough of the bad behavior and attitude of humankind, and has decided to start it all over. It is up to a struggling inventor and a bank teller, both with very amateur criminal minds, to save the world by falling in love.
After dying in a car crash, Bobby Fantana is forced to pay for his misdeeds by becoming someone's guardian angel. He reluctantly agrees to watch over awkward high schooler Lenny Barnes, teaching him how to be cool and confident. As Bobby teaches Lenny, the two form a close bond.