In a world where young minds question the fabric of reality, our male protagonist sets out on a transformative odyssey when he encounters an enigmatic being known as a Solus—an entity resembling humans in every aspect, save for its singular heart, in stark contrast to the norm of dual-hearted creatures. Struggling with amnesia and besieged by the looming threat of the Non-Existent (NE), the boy refuses to yield to his fate, embarking on a quest for answers. Fueled by an unwavering resolve and unwavering courage, he confronts the mysterious Solus, demanding not only the truth about his own identity but also an exploration of the very essence of existence itself. Together, they navigate the labyrinthine streets of an unfamiliar modern city, peering into the depths of humanity and unearthing the boy's true self along the way. Guided by the enigmatic Solus, he embarks on a journey of profound transformation, one that illuminates the enduring significance of hope in the face of life's myriad challenges. "The Unexpected Boy and The Solus" is an exploration of existential inquiries, the profound impact of self-discovery, and the embrace of life's inherent uncertainty. A narrative poised to captivate young readers who found joy in "How do you live?" and "Valentine Crow and Mr. Death," it invites reflection upon one's cosmic place and the profound significance of one's existence as it unfolds.