Robin is unreliable, unstable and utterly devoted to his oldest friend Henry. So when Henry's beloved mother - the novelist Marian Finch - dies unexpectedly, Robin is there to pick up the pieces. Henry comes into possession of an antiquarian bookshop and there - for a time - they build a life together.

But grief can send us down unexpected paths. For Henry, it leads him to the theory of multiple universes and to Yolanda, a brilliant scientist who can help him understand it.

Robin and Yolanda have three things in common: they are in love with the same man, they despise each other, and they are oblivious to the fact that Henry is spiralling into a dangerous obsession that will irrevocably change them all.

Imaginary Forces is a portrait of love in its many forms - yearning, obsession, addiction - and just how messy and destructive it can be.