Fred meets a professor who's more murderous than nutty.

Fred discovers that one of her science articles has been published, and she's been asked to give an address about it. As she does so, however, a portal opens and demonic tentacles try to drag her in.

Nervously, she meets up with her old physics teacher, Professor Seidel, the next day. While browsing his books, she is shocked to discover one full of portal-opening magicks.

Realising that it was he who sent her to Pylea, Fred determines to kill him. Helped by Wesley, she goes to Seidel's office, only to find Angel and Gunn there, both of whom are trying to stop her.

As Angel battles a demon, she opens her own portal to kill the professor. To prevent her, Gunn steps in to do the job himself.

Quiz - ten quick questions.

Trivia: The supersymmetry of the title is a branch of very very complicated physics called string theory that tries to tie all theories together with one Unified Field Theory. It involves lots of dimensions and big long difficult equations.

There's a whole raft of comics references in this episode. Gunn mentions Daredevil 181, in which issue, as his threat suggests, Elektra dies. But don't worry kids, she's got her own book now.

Comics publisher Dark Horse is also referred to. One of the largest US comics companies, their title include none other than the Buffy series. They have also published an Angel series.