A Weekend (Girls' Night) in Leanbox (リーンボックスの週末（ガールズナイト）, Rīnbokkusu no Shūmatsu (Gāruzunaito)) is the third episode of Hyperdimension Neptunia: The Animation. It was first aired in Japan on July 26, 2013.
In Leanbox, 5pb. performs in a large concert held in a stadium. Among the crowds are IF, Compa, and the CPUs, excluding Vert. Underwater, Warechu finds and comes across a glowing, red, cross-shaped object.
Wondering why Vert didn't go the the concert, the group goes to Vert's residence. Trying to find Vert, Neptune comes across a room full of games, figurines, and pictures. Nepgear overhears Vert's voice and finds her room. Noticing the group, Vert explains that she stayed behind because she got caught up with a video game. Blanc reminds Vert that she was also suppose to throw a party for the group after the concert, but Vert says that she's still in the middle of a game. Forced to wait, Noire decides to prepare for the party and also getting the rest to do so. Nepgear, IF, and Compa are assigned shop for ingredients, while the rest cleans up the room where the party will be held.
After shopping, Compa is on her way back to Vert's residence. At the same time, Warechu is running when he suddenly trips, dropping the red object in the process. Compa notices him on the ground and checks him for any injuries. Noticing a slight bruise, Compa puts a bandage in Warechu's arm. Nepgear arrives and notices the dropped red object. Picking it up, she suddenly feels a painful sensation. Warechu grabs the object back and runs away, coming across IF who spots him.
Back in Vert's residence, the group are able to prepare for the party. Vert decides to show the group a game. Using Neptune and Noire as participants, Vert demonstrates the game's capabilities, morphing their appearance into Dogoos and leading them to fight in the game. Somewhere, Warechu meets Arfoire and hands her the red object.
Vert receives information that a large amount of monsters showed up in a waste disposal plant in the Zune district. Vert decides to handle the situation, and Neptune, Blanc, and Noire decides to tag along. The CPU Candidates also want to come, but the CPUs dissuade them. The CPUs transform to HDD form and head out for the waste disposal plant, where Arfoire and Warechu is seen with a bunch of monsters.
IF informs Compa and the CPU Candidates about the information she gathered about the same mouse she spotted in the shopping mall. She tells them that Warechu is apparently in every nations' blacklist and was spotted boarding a ship to Zune district. IF decides to check things out there. Worried about her sister, Nepgear decides to tag along with IF.
The Hearts arrive at the waste disposal plant in the Zune district, gaining a visual of the monsters. Larger monsters suddenly appear, but the CPUs eradicates them all. They're abruptly grabbed by wires, putting them in a bind. Then Arfoire makes her appearance and seals them inside a large prism formed by the red objects she gathered. Arfoire reveals that the red objects are Anti Crystals, stones that robs the CPUs of their powers and abilities by severing them from their Share Crystals. Warechu takes pictures of the incapacitated CPUs and plans to spread them throughout the world. IF and Nepgear arrives in the location, and they spot the CPUs enclosed inside the prism.
- Arfoire revealed that the glowing, red, cross-shaped objects were Anti Crystals, stones that robs the CPUs of their powers and abilities by severing them from their Share Crystals.
- The CPUs were incapacitated and confined inside a large prism formed the Anti Crystals.
A Nepstation broadcast is broadcasted, which was recorded before the CPUs were captured. Neptune and 5pb. advertises their viewers to get Dimension tripper!!!!.
IF, Compa, and the CPUs, excluding Vert, goes to a 5pb. concert in a stadium located in Leanbox. Nepgear, IF, and Compa shops for ingredients for the party in a shopping mall in Leanbox. The CPUs battle monsters and are eventually bounded in a waste disposal plant in the Zune district.
Characters are shown in order of appearance. An asterisk (*) near the name means the character have debuted in this episode.
- A controller resembling a Xbox 360 controller is briefly shown when Vert is showcasing her game.
- A segment of Nepstation, a feature in Hyperdimension Neptunia Victory, is shown in the end.
- 5pb. singing Kirihirake Gracie☆Star may be considered symbolic as this episode begins the loose adaptation of Hyperdimension Neptunia mk2, which Kirihirake Gracie☆Star was the theme of.