What if no one will accept who you really are?
What if you finally get the chance to make them pay?
David is quite sure he knows who he is, and sure his mother is alive, even if he has just read her obituary... while talking to her on the phone. So something's not real. Imaginary numbers of somethings aren't real, or at least, aren't quite who or what David thought they were. And perhaps he'll have to love himself before he can work it all out and love somebody else.
Find it on Amazon at https://www.amazon.com/Imaginary-Numbers-Mathemafiction-Sheila-Deeth/dp/1949600564/
And watch for the sequel in Book 5. (Of course, I'll have to get the story out of my head and onto the computer first...)