American Gods by Neil Gaiman

After three years in prison, Shadow Moon is free to go home. But hours before his release, his beloved wife is killed in a freak accident.

Numbly, he boards a plane where he meets an enigmatic stranger who seems to know Shadow and claims to be an ancient god - and king of America. Together they embark on a profoundly strange road trip across the USA, encountering a kaleidoscopic cast of characters along the way. But all around them a storm of unnatural proportions is gathering.

War is coming, an epic struggle for the very soul of America. And Shadow is standing squarely in its path.