Blue Drop

Mari fails the semester exam and is forced to study with Yuuko in order to prepare for the exam. Mari studies diligently and extracts a promise from Yuuko to join her at the fireworks festival if she passes. Due to Hagino's insubordination, Shivariel sends two ships to destroy Blue. Meanwhile, Mari overhears that Yuuko is a special investigator attempting to uncover Mari's memories of the incident five years prior. She runs away into the woods followed by Yuuko, and the two are attacked by Azaneal. Hagino arrives and defeats Azaneal, just as Tsubael has Blue cripple its opponents. Following this, Mari asks Yuuko to stay at the school, even though Yūko was planning to leave due to her cover being blown. (Source: Wikipedia)