The episode begins with Master Shake and Meatwad watching television in Seattle. They are being watched from outside by a pair of Skeletons who are outside in a surveillance van. Believing that the Aqua Teens are aware of their presence, they cause a satellite fire at the Aqua Teens' house. Knowing that this is about to happen, Master Shake and Meatwad grab a confused Frylock and get away in an escape shaft before the house is destroyed. Hearing this from next door, Carl arrives and sees that the Aqua Teens are gone. It is then revealed that Carl is a spy working for the president who has been studying the Aqua Teens for ten years (also, he actually doesn't have a mustache). Carl then confronts the skeletons, telling them that they have failed, before shooting the van until it explodes.
Underground, Shake (Flint) and Meatwad (Ryan) interrogate Frylock, whom they believe is a double agent. Carl (Lars) secretly listens to the conversation from his home. Meatwad pulls a gun on Frylock, and discusses the death of a former Aqua Teen, Napkin Lad. A flashback then shows Frylock and Napkin Lad somewhere in the middle east, with Napkin Lad tied up. Frylock then fakes an ambush, and hands Napkin Lad over to Carl and a group of skeletons. Carl then hears three gunshots, and assumes Frylock has been killed. However, the camera pulls back to reveal that Meatwad had actually killed Master Shake, and escapes with Frylock. Meatwad and Frylock then drive off in the Danger Cart, which is a car in this episode headed for South America, but Carl discovers the ruse based upon a recording from Shake, who expected his demise and Carl's true identity and tells them of their intended location. Carl pursues in 2 Wycked, accompanied by Napkin Lad, who has secretly been working with Carl all along.
A car chase ensues, and Meatwad eventually drives off a cliff, into the ocean. Napkin Lad thinks that the Aqua Teens didn't survive, but the cart turns into a submarine (as does 2 Wycked). The chase continues underwater. Frylock pulls a gun on Meatwad, meaning he actually was a double agent. But, Frylock discovers that he was betrayed by Carl who helped fake Napkin Lad's death, while Frylock was out buying blue jeans. Meatwad then escapes the cart before it crashes into a reef, killing Frylock. Seeing this, Carl then shoots Napkin Lad, saying "you've seen too much, and you know too little". However, the gunshot causes 2 Wycked to explode.
Back in Seattle, Meatwad leaves the house. He is met by Carl, and both of them pretend not to know what happened earlier.
- Two Skeleton spies are shot to death by Carl.
- Master Shake is shot in the head by Meatwad.
- Frylock crashes his underwater car, killing him.
- Napkin Lad is shot to death by Carl.
- It is revealed in this episode (although the show is rarely ever canonical) that Carl's mustache is actually a fake, similar to his look in Remooned.
- Napkin Lad is a character originally pitched by Todd Hanson in the Baffler Meal episode of Space Ghost Coast to Coast to be an Aqua Teen. He was meant to have a cheery attitude and promote cleanliness, until Zorak poured water all over him.
- The Kill Dummy makes a cameo appearance as camera 04 in this episode.
- This is the third episode in the series to have "Last" in an episode title.
- While this is the confirmed title on [adult swim], it is shown on the DVR as "Spy."
- Meatwad's hair at the end might have been modeled after Boxy Brown.
- All censors in this episode are not audible. They are just mouthed by the characters.
- The puppet show from The Creditor is revisited.
- The Danger Cart reappears, and as like the opening theme displays it, attached to the car Meatwad and Frylock take. The Cart still reads Aqua Unit Patrol Squad, as it did in Allen Part 1.
- The song "Big Foot" by Chickenfoot is featured in this episode. The episode aired prior to the official release of the song. "Big Foot" is one of the few "real world" songs to be featured in its original form on the show.
- The Powerpuff Mall is visited once again, though it looks entirely different.
- The hat Frylock wears at the Powerpuff Mall is the hat Shake wore in his disguise as Jacques.
- The Skeletons' van is the same van that Terry uses for travel Plastic Surgery in Laser Lenses.
- In the broadcast version, Meatwad says "Frylock, get in the damn chair!" while the in the DVD version, he says "Get in the god-damned chair!". In addition, the way he says it is different in both versions.
- Meatwad, Shake, and Carl's "real" names are revealed to be "Ryan", "Filnt", and "Lars".