Gravitation is a shonen ai "boy love" anime that follows the love story of nineteen-year-old Shuichi Shindou and Twenty-two-year-old Eiri Yuki.Shuichi is an upbeat, charismatic singer of the band Bad Luck, while Eiri Yuki is a cynical, cold romance novelist who has never truly fallen in love.
The story revolves around their meeting, interactions, and eventual falling in love. Unlike most shonen ai animes, this one takes a more realistic approach to love; it does not happen instantly; it progresses over time. Yuki has had a hard life prior to meeting Shuichi which is the reason why he is so cold and untrusting, though Shuichi persists with a feiry passion to pick away the ice that has encompassed itself around Yuki's heart.
Their love slowly blossoms as the ice begins melting, and Yuki becomes more active in supporting Shuichi in his music career.
Shuichi has a cast of friends that are always there for him, incluiding Hiro, the guitarist, and Fujisaki, the pianist. Hiro is noted as being Shuichi's closest friend and is always there for him when he's down, even going so far as to threaten Yuki by telling him that he will hurt him if he ever does anything to make Shuichi sad. Fujisaki is more of a passive character that merely tends to blur into the background.
Ryuichi is another of Shuichi's friends. He is a singer from a band that Shuichi idolises called Nittle Grasper. Most of the time, he acts as if he's oblivious and childlike, sometimes talking through his stuffed bunny, though when it counts, he knows just how to get Shuichi back up on his feet.