Novel_guide

In Volume 1, Aya and Tooya are married and their daughter is named Miku. Yuuhi is studying for his Chef's exam.
Alex has secluded himself off the coast of Tokyo on an uninhabited island where Kagami had a secret lab. After some serious deliberating, he decides to gently dispose of the feterlized Tennyo eggs. He tosses all but two of the capsules into the ocean. The two he didn't dispose of he would give a proper burial since he knew their mothers.
However, the morning of the burial, those two capules spontaneously gave birth. As if that wasn't enough, a third he had dropped also was born.
He became a father to the three girls, raising them on that island (it's so kawaii too ^_^). He even developed a machine that would nuture their intelligence although he never made mention of of the concept 'family'. They grew up surprizingly fast and by three year's time appeared to be sixteen.
Druing all this time, Alex had been secretly collaborating with Lulik, his old assistant from Project C, to help these girls as they were Tennyo and could very well die. The girls overheard and decided to run away. But not before asking Alex to give them proper names.
The first two were no problem, since he knew their mothers. Miori and Chidori. As for the third, he ended up blurting out his favorite anime character, Shiori.
The girls drugged Alex, hacked into his files concerning the C Project, and left in search of their mothers and identities.

Volume 2 mostly follows his 'daughters', Chidori and Miori, around as they find out more about their mothers and themselves.
Chidori meets up with Yuuhi, almost thinking for a time that she really is Chidori. Meanwhile Miori almost follows in her mother's footsteps and finishes her revenge.
But she is stopped by Shiori, who had been taken in by Aya and Tooya since she had amnesia, and led to reconciliation by Aya, Tooya, and Chidori, who had arrived to visit the couple.
Shiori by this time had become a full Tennyo and decided to fly away with Miku.
Meanwhile, Alex is feeling guilty, thinking that he didn't raise his 'girls' right, forgetting to love them as a father should. He hasn't eaten nor slept since they left. However, he gets a big shock when Kagami enters the lab. At first Alex thinks he's dead, but then realizes that Kagami was saved from the burning ship by Ragnaleck, the shady financeers behind Project C.
Kagami commands Alex to restart making mana for Ragnaleck, who he's now loyal to, because Lulik's research fell into the group's hands and they accidentally released a deadly virus on the world, the Ceres Virus.

Volume 3 reveals Shiori's role as Kagami's spy. In reality, she had kisnapped Aya and Tooya's daughter. However, when she learns the truth about her mother commiting scuide with the other Tennyo in the lab and being named after an anime character, she returns to the island with Miku in tow.
She confronts Alex about her past and demands the mana he made so she could leave this world. He refuses, saying that it would kill her and he doesn't want that to happen because he loves her.
Eventually Miori, Chidori, Tooya, Yuuhi, Kagami and crew, and Ragnaleck shows up. Shiori decides to fight to protect Miku, who has the power to cure the virus.
Even though they defeat Ragnaleck, Miku and Tooya fall into the ocean and those on the island are now infected, Alex among them. When it seems that the world is about to end, the collective conciousness of Ceres emerges from the sea and summons all the decendants of the Tennyo, including Suzumi and Aya, to come together and heal the world. Miku is returned to Aya although there is no sign of Tooya.
Miori decides to help others by becoming a nurse. Chidori stays with Yuuhi, finally confessing her love for him.
Shiori stays on the island with Alex, becoming his companion and promising to be a mother to any Tennyo children who emerge from the sea if he will be their father. ^_~
And Tooya does come back from the sea to be with his daughter and his wife, who is pregnant again.