Duke Milian Pastellio, the ruler of the wintry and demon-infested territory of Zentar, is greatly disturbed when he receives news that his fiancée, Karina Leopold, has arrived without notice. He has never liked Karina and had hoped to avoid seeing her until their wedding. However, Karina has firm demands: she wishes to reside in Zentar for several months and then end their engagement, after which they shall part ways forever.

Although Karina asks for no attention, Milian worries about her weak constitution and frequent bouts of illness. In fact, Karina suffers from the incurable art disease—a condition where exceptionally skilled artists can perform miracles such as bringing their pieces to life at the cost of their own wellbeing. As Milian takes a shine to Karina, he desperately tries to find a remedy for her symptoms and alleviate her misery. Appreciative of Milian's efforts, Karina hesitates to reveal the full truth: she has the rarest type of art disease, and no treatment will prevent her impending death.

Karina's Last Days has been published digitally in English by Tapas Media since March 2, 2022.