Ari is a space gunner aboard the Garuda, a ship traveling through the galaxy in attempt to hunt down a theriida: a violent space whale possessing organs and skin that can provide riches and protect humans against interstellar radiation. The radiation the creature's heart emits, however, has the capability to disintegrate human bodies and transform them into theriidas themselves. On the ship, Ari is accompanied by Nate, the captain, and Eliot, who is both the engineer and Ari's lover. The team of three are known to be the best at their respective jobs, at least "on this side of the Mercy War." When they finally trap a theriida and slaughter it, Nate exits the ship to collect its skin, also known as its plasma. In their greed, the team decides to risk removing its heart, which is valuable enough to make them extremely rich upon returning home. Nate discovers, however, that the theriida in fact has forty hearts, each indicative of one of the creature's offspring. The radiation from the offspring kills Nate and turns him into a theriida. Ari and Eliot sense their approaching doom. Before the radiation reaches them, Eliot programs Ari into the ship—uploading her into the Garuda's core. He then disintegrates and is transformed into a theriida. Ari, now the _Garuda _itself, spends her days following the theriida Eliot has become throughout the galaxies, protecting it from other space hunters.