A new teacher at Springfield Elementary, and a captivated Bart tries everything to win her over. Meanwhile, Homer decides to buy a new brand of "milk," which causes early puberty, both for Bart (augmenting his wooing powers) and Lisa (whose small bout with acne opens her up to the world of makeup and popularity).

Lonely Professor Fink uses science to turn himself into a man whom women find attractive. Then, overwhelmed by the attention, he invents an algorithm to perfectly pair the lonely men and women of Springfield, realizing that scientific exploration is his true love. Meanwhile, Marge, Bart, and Lisa visit Grampa for Valentine's Day and try to rescue the old folks from a drug-induced hallucination that allows them to relive their happiest memories.