The UNSC Advent Children (CVG-124) was a Odin-class Carrier and leader of Battlegroup Advent Children. It was sent to investigate the lack of transmissions or transports from the border world Linna. Upon reaching the system they discovered the hulk of the UNSC Arsenal, stripped off life. After recovering its black box it learned of its fate. Upon pressing further into the system it discovered Linna, lifeless and devoid. However, on the far side of the planet, a battlegroup of unidentifed vessels lay in waiting and immediatly launched an assault.