Mendoza, imprisoned alone billions of years in the past, is suddenly and unexpectedly visited by someone who looks a lot like not one but two other men she loved and lost under various violent and traumatic circumstances and despite knowing that history has every chance of repeating, she falls for him all over again, and even advises him on various ways of carrying on his time jaunt without dying. But how does this mysterious third iteration of something even a immortal time-travelling preservationist cyborg has a hard time crediting come to exist?

Way up in the future, close to the fabled blackout point from whence no report comes, four history buffs in a highly constrained world who are part of the Dr Zeus company invent a new type of enforcer. Alec Checkerfield is one of them, and this is his life. Staggeringly priveleged but deeply dysfunctional, he hides his genius and sails the world with an artificial companion he, at first inadvertantly, turned into the most powerful AI in the world. Searching for a purpose and a way to do good, Alec gradually homes in on the truth of his origins, following the path that will eventually lead to Mendoza, and then on further still to utter catastrophe.

I love these Company books. Witty and clever, they are also dark and exciting. I was also very pleased to come across a Dorothy Dunnett reference.