From MangaHelpers:

Four years ago, Takashi, Makoto and their close group of rugby friends, who called themselves the Invincible No Pain, made a pact: to get into the same high school and beat Sone Kogyo, the extremely dominant rugby school in the region. Even though Makoto had to move to New Zealand, the rest of the crew kept their promise and attended the same school to defeat Sone, who made nationals year after year. But the result ended up in disaster when they were crushed so badly that it broke their spirits and the members of the Invincible No Pain decided to never play rugby again. But when Makoto comes back from New Zealand as an inspirational and amazing rugby player, he convinces the team to stand up once again and keep their promise they made years ago. [vyc]