After a sickening display of Master Chief's behavior around girls on Xbox Live, the Arbiter takes it upon himself to teach Master Chief how to act appropriately around women.

Inspired by seeing the new Forge visual filter objects in the Legendary Map Pack, Master Chief is inspired to create his own map.

After the Arbiter plays a headache-inducing game with a few super serious Halo 3 players, Master Chief inquires about a mysterious package that has been delivered to Jon, the house owner, and discovers later that night that the contents of the package will change his and the Arbiter's lives forever.

Consumed by envy, Chief seeks to end Cortana and Todd's relationship by any means necessary.

Todd has stolen the love of Master Chief's life, and Travis has made a complete fool out of him. As a result, a disgruntled Chief approaches the Arbiter during an irritating game of Grand Theft Auto IV online and tells the Arbiter of his plans to teach Todd and Travis a lesson that they will never forget.

Picking up from where episode 11 left off, Todd, Travis and the Chief get into an epic rumble that eventually gets broken up by the Arbiter and Cortana. However, the next morning, Todd and Travis are nowhere to be found, and Cortana blames the Chief... but did he really have anything to do with their disappearance?