Rin and their flatmates have settled into a regular routine. Sanjay is busy dating. Pete has some new theories. Rin is just trying not to upset anyone. Then the aliens interrupt their winter celebrations to ask for help. A shapeshifting tree has gone missing. A colony of werecockroaches is the obvious choice to solve a magical mystery, as far as the aliens are concerned. Rin is not so sure. They don't know anything about weretrees. But with a few other friends along to help, maybe it's not so hopeless after all.