Sleepover Argument is the second episode of The Marvelous Adventures of Luna and Luan.
When each of them have a sleepover on the same night, Luna and Luan argue over who is using their room.
The episode starts in Mrs. Act's 3rd period class, and after some conversation, Luna invites her friend Gabbi over for a sleepover on Friday, unaware that Luan also invited her friend Andrea to have a sleepover the same night. Neither of the sisters wants the other to know about the sleepover, so they each come up with excuses that makes the other think that the room will be available for Friday.
Soon enough however, they figure out that the other one is having a sleepover, and each wants to use their room on Friday. Luan states that Luna has had more sleepovers, and has used the room more times, so she should get it, but Luna says that the number of sleepovers doesn't matter, but Luan has trashed the room every time she has a sleepover. This gets the sisters to argue and fight until one of them gets the room.
Friday night comes and they haven't reached an agreement, so Luna and Luan tell Gabbi and Andrea to sit in the living room and watch a movie while they "set up". After another hour of this argument , they begin to fist-fight, and before things get really violent, Luna realizes that the living room has a tv, and their room doesn't. So Luna tells Luan that she can use the room. Then the sisters walk downstairs to greet their guests, but they see Lincoln on the couch, crying because of how sweet the movie was. He then informs his sisters that their friends left, because they thought you would rather hang out with each other.
Initially saddened upon hearing this, the girls then make the most of the situation, by having a sleepover together with Lincoln. The three of them played board games and watched movies in the living room all night long. The episode ends with the sisters staring at Luna, Luan, and Lincoln all passed out in the living room.