Dengeki Stryker is an eroge, or hentai video game. The story revolves around Yamato Yuuki, the story's principle male protagonist. As a child, Yamato was a fan of a superhero manga by the same title of this game, and wanted to be a superhero to better defend his friend Haruna from the bullies that constantly tormented her. One afternoon, after Yamato had suffered a severe beating at the hands of Haruna's many bullies, an old man known as the Memory Collector, approaches him and offers Yamato the chance to be a superhero if he's willing to forsake his childhood memories. Yamato readily jumps at the offer, and despite not knowing who or what he is, Yamato begins to fight against evil as Stryker Zero.

Sayaka works as a waitress at Cafe Ichimonji. She is the game's tsundere, and although she enjoys seeing Stryker Zero, is always bothered that Zero only offers one cup of coffee.