The Raw Shark Texts

Eric Sanderson wakes up in a place he doesn't recognise, unable to remember who he is. All he has left are journal entries recalling Clio, a perfect love now gone. So begins a thrilling adventure that will send Eric and his cynical cat Ian on a search for the Ludovician, the force that is threatening his life, and Dr Trey Fidorus, the only man who knows its secrets.

Synopsis from Open Library.