After learning that both Yuki and Shiro are pregnant via divine power and he is the father, Masaki meets another girl who is ideologically perfect for him. Perhaps a little too perfect.
Maternal September contains the following examples:
- Artificial Human: Yukari Nakahira was created by Shiro's magic.
- Battle Aura: A clear one for Yuki and Shiro in a CG image.
- Bait-and-Switch: Masaki is getting another girlfriend?! Oh, wait...
- Continuity Nod: To the Babysitting Episode events of March.
- Downer Ending: Yukari disappears after leaving Tagami's boundaries with no one remembering her and Ao has her heart broken.
- Foreshadowing: Ao's being able to sense something familiar about Yukari.
- Here We Go Again!: Yukari confesses to Masaki and asks to date him for just a month. He accepts.
- My God, What Have I Done?: Masaki after the reality of the Here We Go Again! above hits him.
- OOC Is Serious Business: The fact that Yuki and Shiro aren't killing Masaki due to his agreeing to date Yukari for a month has him very much on edge.
- Papa Wolf: Yukari's father is described as "hiding something lethal behind his back" when being introduced to Masaki. He later beats Masaki unconscious with a golf club.
- Secret Test of Character: So secret even the test giver wiped her own memories of the test!
- Tastes Like Diabetes: In-Universe a lot of people describe Masaki and Yukari as this when they're together.
- Tempting Fate: Masaki thinking he can fold and put away Yukari's lingering pair of panties before she returns to her room after wasting several moments deliberating/rationalizing the act with himself.
- What the Hell, Hero?: Another one given to Kouhei. This time from Yukari.