.hack//Sign is set in the world within an online game. Tsukasa, a powerful Wave Master, finds himself lost in the cyberworld, with little memory of how he got there. More significantly, he's unable to log out of the game and is apparently immune to many of its restrictions.

He may be the focus of an impending crisis linked to the mysterious Key of the Twilight. As he wanders through different realms, Tsukasa meets spunky girl warrior Mimiru; earnest soldier Bear; the Crimson Knights, who maintain order in the game-world; and genially heroic Crim, a Heavy Spear wielder.

Tsukasa also encounters a potent but unseen entity who promises to protect him--and does. Handsomely designed, well animated, and skillfully directed, .hack//Sign stands out as an example of how to turn a game into a series that can stand on its own merits.