"Master Chief Sucks at Shopping" is the third episode of season 3.
The King tells Johnson that past-Ronald doesn't hate him yet because he hasn't quit McDonalds yet, at which point Master Chief arrives and tells the employee King to quit his job. Past-Ronald asks the King what he needs, and the King explains that he met Ronald when the latter was time travelling. The young King is inspired by the future King's costume. The King says that he was sent back in time (leaving out who it was that sent him back) and asks for help returning to the future. Ronald agrees to assist them.
Master Chief and the Arbiter are told by Guilty Spark to buy weapons, and Master Chief suggests shopping at Walmart, the only store still open in the post-apocalyptic future. Master Chief explains how to park at Walmart and describes its typical customers as redneck white people (claiming that minorities are barred from entrance because of Jim Crow laws). Eventually, the pair are refused purchase of weapons because they don't have a license, prompting Master Chief to create an angry mob as a distraction by claiming the clerk is gay. After stealing weapons and fleeing, the pair encounter Guilty Spark again. He explains that Cortana is dead, but because she is an AI, she can be rebooted if someone retrieved her activation codes. Her codes were retrieved before the Ark exploded by a program called "The Senator," better known as Hillary Clinton. The activation codes are stored on the Halo ring and guarded by a program called the Governor. The pair decide to go rescue Cortana. After the credits, Cortana can be heard telling the Governor that her friends are coming and ready for a fight.
- This is the first traditional episode since early season 2.
- The King creates a predestination paradox when his future self's costume inspires his past self to make it. Similarly, the future Master Chief inspired the past Johnson to create his own armor design.
- Cortana is a guest star for the first time since the minisodes. She was a main cast member during season 2.
- At one point, the Arbiter decides to try and give advice about shopping. Master Chief interrupts him in a parody of Kanye West and explains that the video is called "Master Chief Sucks at Shopping," not "The Arbiter Sucks at Shopping."
- Cortana having a discussion with her captor after the credits is an homage to the end of Halo 2, where Cortana has a conversation with Gravemind, who is holding her prisoner.
- This episode contains references to the first two episodes when Master Chief explains how parking at Walmart is different than at McDonalds or at restaurants. ("Master Chief Sucks at Ordering McDonalds") ("Master Chief Sucks at Ordering at Restaurants")
- The King and Johnson witness the time travelling Master Chief telling past-King to quit McDonalds. ("Master Chief Sucks at Time Travel")
- The running gag from Meet the Ancients, the iGame and Megan Fox Sex Simulator, are mentioned when Master Chief is distracted by the products at Walmart. ("Meet the Ancients")