Tatsuhiro Satou is a 22-year-old hikikomori who dropped out of college and is now entering his fourth year of unemployment. He consumes hallucinatory drugs to escape reality, leading him to come up with various conspiracy theories. One such theory concerns the existence of a secret organization called the Nihon Hikikomori Kyoukai (NHK), which is supposedly responsible for Tatsuhiro's shut-in nature and the increasing number of hikikomori people across Japan.

On a quest to fight back against NHK, Tatsuhiro swears to leave behind his socially inept self. However, Tatsuhiro soon realizes that socializing may be too far-fetched a dream for him, as he struggles to get through even the most basic interactions with others. With the help of the mysterious Misaki Nakahara, who claims she can cure him of his current lifestyle, will he be able to turn his life around?

NHK ni Youkoso! is the manga adaptation of Tatsuhiko Takimoto's novel of the same title published on January 28, 2002. The manga series was published in English as Welcome to the N.H.K. by Tokyopop from October 10, 2006 to September 16, 2008. VIZ Media republished the series digitally under the VIZ Select imprint from June 16 to December 9, 2015. It was also published in Brazilian Portuguese by Panini Comics from November 2010 to February 2012.