Nanomachine. Volume 3

The third volume of a popular Korean web novel about a prince with a nanomachine inside.
The son of the powerful leader of the Demon School continues his training. But to pass the most difficult test, he needs to be a master of the highest combat rank. This means he must leave his team and train in a closed room. But how long is Cheon Yoon planning to be absent? And will his team be able to complete the homework assigned by their master and pass the fourth exam on their own?