After a field trip to the desert, Lisa discovers that a desert flower mysteriously makes typically combative creatures get along, so she brings some of the flowers home as a souvenir. When Grampa moves in with the family after getting kicked out of the retirement home, Homer secretly tests the flower on Grampa, who is instantly cured of his crankiness. Walter Hotenhoffer gets word of Homer’s discovery and quickly tries to replicate the flower 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.
The episode received 6.20 million viewers, and was edged out by the new episode of "Family Guy". Rowan Kaiser of the A.V. Club found Lisa's varied options annoying, but praised Herzog's performance. He gave the episode a "B-", the second highest rating of the night (next to Bob's Burgers).