Hiiro, reincarnated as the third prince of a minor nation.

He expected to live a carefree life, but his nation was utterly impoverished, and nothing went as he wished.

One day, he encounters a legendary alchemist, apprentices himself, and masters alchemical magic.

Having learned alchemy, he finds he can now realize Japanese technologies—previously mere ideas—through alchemical magic, leading his nation towards prosperity.

Thus, the Alchemist Prince's nation-building project begins here and now!