River of No Return: Penguin Picks

First, he learned the Rules of the Guild. 

There were only four:

 There is No Return.

 There is No Return.

 Tell No One.

 Uphold the Rules . . .' 

 

On a battlefield in 1815 Lord Nicholas Falcott faces death and instead of dying jumps two hundreds years into the future. There he learns that he is one of a band of mysterious time travellers called the Guild. He may have escaped death, but he is not free as the Guild's rules forbid returning to his old life lest he tear the fabric of time. Yet Nick yearns for 1815 and Julia Percy, the young woman to whom he'd like to give his heart. If he breaks the rules he risks unravelling the past and the future. If he doesn't he'll never see his lost love again . . .