Tantei wa Mou, Shindeiru.

Kimihiko Kimizuka has always found himself in the most unlikely of places at the most inopportune times, often stumbling into dangerous situations and emerging unscathed, much to his own chagrin. His life took an even more bizarre turn when he became the sidekick to a brilliant, if eccentric, detective named Siesta. Their adventures spanned the globe as they pursued mysteries and confronted shadowy organizations, a thrilling partnership that defined Kimihiko's extraordinary, yet begrudgingly accepted, existence. But that was all in the past. Now, a year after Siesta’s untimely demise, Kimihiko attempts to lead a normal high school life, eager to leave his detective days behind. However, fate, it seems, has other plans. When a mysterious girl with an uncanny resemblance to Siesta appears, carrying a secret that could unravel everything, Kimihiko is once again drawn into a web of intrigue, proving that sometimes, the past isn't quite ready to stay buried.

✦ AI-drafted summary