The twins try to behave normally with their father or his pod person, whichever the person who calls them is, for a value of "normally" that involves adamantly continuing to want nothing to do with the Sharing.
And sometimes crying and refusing to tell Renée what's wrong.
School proceeds. No one's grades see more than a minor downturn as a result of all the alien business.
Andi and Robin play music. Andi's getting pretty good on the drums, although her teacher moves away and she has to hunt up another one, who she sticks with for four lessons before deciding to go self-taught.
Bella tightens up her cipher. It began as a letter substitution and since then has evolved to include plenty of personal shorthand - she turns the ratio of shorthand to straightforward letters up as far as she can and still read the thing herself. She abbreviates, she leaves out spaces, she names things in roundabout ways, she refers to things many notebooks ago that she can find easily that anyone else could spend hours hunting for, if she has to record names she finds ways to describe the spelling without ever placing all of the characters in sequence. Maybe the aliens have super-cryptanalysis and super-OCR and can eat her notebooks in one bite and know everything they know; but maybe not, and maybe if she's careful enough she'll look like she's writing her paranoid diary and not like she's taking notes on the quiet invasion.
Trouble comes over a lot. He stays over a lot. Renée has a quiet conversation about him with Bella, in which Bella is vague, pretends ignorance, suggests that maybe he just likes it here, maybe his folks are allergic to gluten and won't eat his baked goods? Renée leaves it alone.
May begins.
"It was good," Andi calls back. "We're all here, we're gonna hang in the basement for a while."
"Nice and cool. Nice and private," she says, when the door is closed behind them.
"You missed some interesting spectacle." There are folding chairs; she starts unfolding them. Then she gets her notebook out. "Are you guys thinking you want to do something, or would you rather forget you saw anything?"
"We have a resource now. We have information and really killer spy gear to get hold of more. We know what's doing the pod person shtick, we know they have at least one weakness, we know there might be help on the way, and we can - turn into things. It's no longer all we can do to sit around making tentative, useless inferences based on the one alien Robin saw one time. I'm going to figure out how to un-Yeerk Charlie without arousing suspicion, and then I'm going to see where else I can hit them. I know Andi's with me, but the more help I have, the easier it is to accomplish anything."