The Only Light in the Darkness

Dipper has to sacrifice himself to stop Bill. As it turns out, using the memory gun on a still-developing brain has more side-effects than using it on an adult's brain. Now, Mabel not only has to help Dipper regain his memories, but has to help him cope with all the other problems that come with having your entire mindscape erased. Not really any plot, just angst and fluff.