As science progressed, humans began conducting daring experiments, defying the laws of creation. Their leader, called Father Prime, has concocted the most audacious plan: contact Satan. His reasoning is that he who controls the devil will also know how to control God. As the Earth plunges into sin and corruption, God himself decides that time has come to interfere. He sends a little cherub named Bob to investigate Father Prime's designs. Since Bob is endowed with a human soul, he has a free will and is capable of making a decision, even if it contradicts God's orders. With nothing but his frail angelic body, Bob descends into the sinful world.
Messiah is a third-person action game set in urban environments with sci-fi elements. The player controls Bob, who can fly (though at low altitude), but not do much else; he is very vulnerable and can be easily killed. Thus, the player must make use of Bob's other ability: possession. Bob is able to take over any creature, from humans to animals. Once he possesses his target, he has complete control over its movements.