Himitsu Renai Soudan

Yuu-kun and Yuki-neechan were childhood friends. But Yuki had to move away. In desperation Yu-kun gives her a ring and begs her to marry him. Yuki swears never to forget their promise... Now Yuu is in high-school--and Yuki is the school nurse! It seems all she does is tease-tease-tease poor Yuu-kun. Now another girl is confessing to Yuu-kun. Has the promise been forgotten?