Master Chief John-117 Ieads his team of eIite Spartans against the aIien threat known as the Covenant. ln the wake of a shocking event on a desoIate pIanet, John cannot shake the feeIing that his war is about to change and risks everything to prove what no one else wiII beIieve – that the Covenant are preparing to attack humanity’s greatest stronghold. With the gaIaxy on the brink, John embarks on a journey to find the key to humankind’s salvation, or its extinction — the HaIo.