Two bonus episodes that take place during the course of the series, approximately halfway through it seems. They are entitled 'Everything you always wanted to know about Nereids (but were afraid to ask)' and 'Heaven can wait for Maia Mizuki'. These stories are more lighthearted and comedic in tone, bordering on silly.

Bundled with Hiiro no Kakera Taizen, a comprehensive illustration book on the six-year history of Idea Factory's Hiiro no Kakera romance game franchise, the OVA reveals the private lives of the five main characters.

In the future, water has covered much of the Earth due to the effects of global warming. The orphaned Maia Mizuki, 15, just graduated from middle school and has already applied for employment in the elite paramilitary Ocean Agency, part of the futuristic world government. Only the best, most intelligent, and physically fit students are eligible for admission. Maia, the series' protagonist, is set to become one of the few. But her ideal life quickly falls apart. To her disappointment, Maia unexpectedly fails her entrance exams. Making matters worse, she promptly gets evicted from her house, pick pocketed, taken hostage, then shot. She is saved by two women (Rena and Shizuka) that are part of an unorthodox help-for-hire organization called Nereids (inspired by the Greek mythological Nereids ). With nowhere to go, Maia joins up with Nereids, taking jobs from capturing wanted criminals to chasing stray cats, often with unexpected results. Gloria and Yu later join up with Nereids. Daphne in the title refers to a subplot that starts midway into the series and eventually become important to Maia. Brilliant Blue refers to the fact that this is a world covered by water with almost no land. The world consists of vast oceans, a few islands, and floating cities. (Source: Wikipedia)

After battling dangerous creatures once existing only in legend,​ Princess Tamaki begins to deal with her uncertain future as the new Tamayori Princess.​ Once she claims her rightful place as the protector of the universe,​ high school will seem like a breeze - but whether she lives to accept that future is another matter altogether.​ Her five guardians - handsome,​ powerful young men of great power and undeniable loyalty - have vowed to sacrifice everything to protect her.​ But are any of them able to deal with a traitor in their midst?​ And how can anyone deal with such important issues while still maintaining a high GPA?​ (Source: Sentai Filmworks)