Last Round Arthurs, Vol. 4 (light novel)

Now that Rintarou has awakened the power within him, there is somethingcomfortable about his new life...even if he spends his days trying to keep upwith Luna's reckless antics. But this current life has come at the cost ofNayuki's. The only way to save her is to get their hands on the Holy Grail, anobject that's eluded all search parties since ancient times. As this questunravels, Rintarou realizes it might be a little more complicated than heimagined...