Haruka Saiki is a male university student in modern-day Tokyo, sporting black hair and embodying a self-styled "city boy" persona that translates into a flirtatious playboy attitude toward women, though he avoids serious commitment. He wields teleportation abilities, one of several ESP powers shared among his acquaintances. His background connects him to Miyako "Neko" Negishi, a telekinetic classmate, and Keiichiro Yamagishi, who transforms into a lion. The trio is unexpectedly transported to a fantasy dimension during a nighttime meeting, where Haruka accompanies Neko as she is declared the reincarnation of a legendary warrior queen.

In the fantasy world, Haruka's development shifts focus from vanity toward demonstrated loyalty and strategic usefulness. Initially preoccupied with his image, he gradually reveals protective instincts toward Neko, employing his teleportation for reconnaissance and tactical support during military campaigns against the oppressive Eastern Kingdom. His role evolves into that of a dedicated companion, his feelings for Neko deepening beyond attraction into genuine care. This surfaces during reflective moments observing her emotional struggles or when he rationalizes their lack of need for sustenance as evidence of a dreamlike state.

Interpersonally, Haruka engages with figures like the battle-oriented ogre princess Dimida; his typical flirtations are misconstrued by her as pledges of martial allegiance, sparking unintended comedic or action-oriented results. Following the group's return to Tokyo, he processes the dimensional journey as a shared dream, though the experience leaves subtle, unspoken ripples on his outlook. His background and abilities remain confined solely to this narrative.