After spending another Valentine's Day alone, Moe attends a seminar led by Dr. Kissingher in the hopes of gaining more confidence with women. Moe takes the doctor's advice and asks Homer to be his wingman, but Moe becomes distraught when women are drawn to Homer as well. Meanwhile, Marge discovers her first gray hairs and surprises both her family and the neighborhood by going completely gray and sporting a brand new mature do, but Bart is not humored when the neighborhood kids tease him about Marge's look. Later, Marge confronts Homer when she learns that he is becoming increasingly popular with the young ladies, but Homer helps Marge realize that he only has eyes for her and proves that love is still in the Springfield air. Blackboard: 'I will not make fun of Cupid's dink'.

After a field trip to the desert, Lisa discovers that the desert water mysteriously makes typically combative creatures get along, so she brings some of the water home as a souvenir. When Grampa moves in with the family after getting kicked out of the retirement home, Homer secretly tests the desert water on Grampa, who is instantly cured of his crankiness. A pharmaceutical representative gets word of Homer's discovery and quickly tries to replicate the water into a drug, using Grampa as the primary guinea pig. But when the pills get in the wrong hands and are sold on the black market, unexpected side effects of the new drug take an eye-popping toll on the elderly citizens of Springfield, and the Simpsons learn that their new medical cure comes with major consequences. Blackboard: 'I'm not here on a spitball scholarship'.