The grand prize-winning novel from the "Magic I-Land" web novel contest finally gets its long- awaited manga adaptation! Matsuo Mina, a high school girl who dreams of having her self-made "special attack uniform" worn by a man she acknowledges as her ideal gang leader, is suddenly attacked by a random assailant one day. Just as she thinks her life, dedicated to fulfilling her dream, is about to end, she loses consciousness. When Mina regains awareness and opens her eyes, she finds herself in a strange otherworld filled with mist-like steam, pipes, and gears. Confused, she's suddenly confronted by Leon Aster, a man known as the "Delinquent Marquis," who arrives riding a steam-powered motorcycle - and he's a vampire to boot! Witnessing Leon's strength and intensity, Mina is reminded of the yankee movie protagonist she admired as a child and her ideal gang leader. She becomes determined to make him a special attack uniform! However, as Mina pushes forward to achieve her dream, a shocking truth awaits her... In a vibrant steampunk world, an unconventional romantic comedy featuring "delinquents x isekai x vampires" begins!