The Corridors of Time

It starts with a man in prision, waiting for his day in court. He's visited by a woman who offers to pay for the best defence lawyer in the country. All he has to do is a job for her when he is free.

All of which leads to Malcolm becoming involved in a war he never suspected, in places he could never have imagined going. But who is his mysterious benefactor? Is he on the right side of this war? Are the enemy who she says they are? And even if he could go home again, would he want to?

Cute little time travel story from fantasy master Poul Anderson. Short, simply and enjoyable.