Misaki is a mysterious girl who decides to help Tatsuhiro escape his hikikomori lifestyle. She convinces him to sign a contract, involving him in her "big project," with the goal of making him a normal person. Though seeing right through his actions, she tries reading him (beginner's) psychology books in an attempt to click with his feelings and "save" him.
At the end, she tells Tatsuhiro that when she was observing him from her mansion, she thought she had at last found someone who is worse than her. She tries to make Tatsuhiro fall in love with her so he would need her, but when he rejects her love contract, she feels unneeded. As a result, she attempts suicide but fails.
Misaki is admitted to a hospital and Tatsuhiro comes to visit her. She isn't in the hospital room and left a farewell note. Tatsuhiro runs on to a cliff to find her attempting suicide again. When she leans over the cliff, he catches her and explains that if there is someone to be blamed for her miserable life, it must be the N.H.K. He claims the N.H.K. is targeting him and tries to commit suicide but fails due to a cage built just below the cliff.
Tatsuhiro moves to a new place due to his old apartment undergoing construction and starts to ditch his hikikomori life by doing part time jobs. Misaki gives him a new contract stating that they both dedicate their lives to each other and will die together.
In the original manga adaptation of NHK ni Youkoso, Misaki has a strikingly different personality to her anime version. The most notable change is that she is a much worse influence on Satou in the manga. In the anime, the cause of her struggle associating with society is the guilt she feels for the role she played in her parents' death. In the manga, her parents are still alive, but she claims they are dead to guilt Satou into staying with her. The reason she isn't in school in the manga is because she failed the year, and it's heavily suggested this was because she didn't fit in with her classmates. She is informally diagnosed with Borderline Personality Disorder by her school therapist, which is only brought up once but is probably the reason she finds it difficult to make friends with anyone other than Satou, hikikomoris, and people she considers lower than her.
At the end of the manga, Misaki and Satou nearly commit suicide by hiding in the attic of the apartment building as construction workers bulldoze it. At the last second, Satou runs out and Misaki follows him. Satou claims he is going to return to his parent's house and work to become a game designer, and will eventually learn to love Misaki. It's left ambiguous whether that happens or not.
