Suspicious of weekly gate unlockings, Elizabeth suspects her husband Richard of an affair, so she changes the passcode and sets up a hidden camera—revealing a woman named Catherine. Elizabeth leaves divorce papers under the mat, but Richard confesses he had secretly been lending Catherine money for her leukemia-stricken daughter Lily. Elizabeth forgives him, offers all their savings, and helps Lily recover fully. Catherine lands a stable job, and the two families grow close. Elizabeth leaves a new note promising lasting help—and warmly welcomes a desperate stranger who knocks on her door one rainy day.
