From MangaHelpers:

Purinosuke is a 30 year old man trapped in a toy body and is the last remaining member of the human race. When the Moon crashed into Earth and destroyed humanity, he was in space aboard the Prinius working as the apprentice galaxy museum curator. He cryogenically froze his body and transferred his memories into a toy so that he could continue his search for any survivors other than him. Accompanied by his robot maid, Shehera, and a random ghost, Purinosuke has to wander the cold deep space without giving up hope that there is someone out there somewhere. [vyc]