Family Bedrock. Tess Noncoire Adventures, #5

Teenage twins Rod and Sprite Maxwell grew up in the weird world of Science Fiction Conventions, where their oddity fits right in. Their paranormal genes cause interlocking plates of stone armor to form under stress and heat. After years of Covid closures, they eagerly approach BeachCon with their adoptive dad at their side. Invalided out of a UN Black Ops agency, Dad is still capable of keeping his kids out of trouble, if needed.
And it's needed. From the moment the twins step inside the con hotel, they face rogue agents, Russian mercenaries, and worse: their own abusive mother. A web of political intrigue entangles the twins in a witch hunt for their bio father and their genetic heritage, in a battle against paranormals. And then there's the problem of their own first loves and raging hormones.