Green Eyes, Guns, and Dangerous Things

Harry is a Guide with a secret. But when revealed, the whole world seems like it's out to get him. First The Ministry, then an 'Order', and now a hit man from a covert organization bent on eradicating his kind. The hired gun seems to have an agenda of his own though. But what could Tom, an Alpha Sentinel, want from Harry? (A Tom/Harry Assassin, Omegaverse, and Sentinel/Guide AU).