Raspberry played a secondary but crucial role throughout Book XV: What Remains, appearing first to Jolene near the end of our 86th storyline, "Radio Silence," then showing up at a pivotal point near the end of our 88th storyline, "Snafu" before becoming an advisor to the nematode Venerables near the end of the book's final chapter, our 90th storyline, "Fubar."
As for Plum and her rehabilitation, that all got started during our previous storyline, "The Transitive Property." And now we all know!
Nuptials, Page 25