Rewind by Christopher Barnard

Charlie, an outlaw from 2045 AD, wakes up to find himself in the last ice age. Adopted by a tribe who find him on the freezing tundra, he is for the first time part of a family. He falls in love with the chief’s daughter, but she is already the object of a murderous obsession by a man who doesn't take kindly to Charlie's interest. A violent revenge is plotted. If Charlie is to save the tribe, he must put aside his own selfish interests. And with Charlie, that’s easier said than done.

“Great Read!! I love the premise. To send a person no one will miss, to become someone that nobody will ever forget.” – Amazon reviewer