My Sister, My Writer

Yuu Nagami, a light novel author, frequently enters writing competitions but has yet to win. His sister Suzuka, who writes under the pseudonym Chikai Towano, dominates the latest contest, and Yuu discovers her identity. Suzuka requests that Yuu take her place, so he agrees to pose as Chikai Towano, with one condition: he'll maintain this fiction until he publishes his own book.