In season two, Master Chief John-117 leads his team of elite Spartans against the alien threat known as the Covenant. In the wake of a shocking event on a desolate planet, John cannot shake the feeling that his war is about to change and risks everything to prove what no one else will believe – that the Covenant is preparing to attack humanity's greatest stronghold. With the galaxy on the brink, John embarks on a journey to find the key to humankind’s salvation, or its extinction: the Halo.

• Pablo Schreiber
• Natascha McElhone
• Joseph Morgan
• Shabana Azmi
• Christina Bennington
• Natasha Culzac
• Olive Gray
• Yerin Ha