From Awakened Memories:
Wakaba got locked up in an elevator with a completely strange guy. Moreover, they happened to share a kiss. He's someone she'd never meet again...or so Wakaba thought, but it turned out that that guy, Chitose, is the boyfriend of Nao, her friend! Nao introduced a surprised Wakaba to her upperclassman in her club, Takaomi, but no matter what, Wakaba can't forget about Chitose....