You can help aunt Douie to harvest plum when:We can't help aunt to harvest plum?
- it's plum harvest time (4 days out of 14)
- at 15 PM or 16 PM
- if your progress with aunt Douie is >= 15
- if your affection with aunt Douie is >= 80
(and if you've not temporarily disabled the plum harvesting schedule, of course).
Just talk to here in this case, and she will ask to help her to hold a ladder for her: