Vol 1. Two in the Bird
Meet Son and Daughter, and Mom and Dad, and some monsters and some other people and some of them die and it's fun. Someone gets hit in the head with a toaster.
Vol 2. Car Trouble
Daughter and Son meet more people and more monsters. Son likes ZOMFU. Daughter likes taking things. OH NO SOMEONE IS TRYING TO KILL THEM! Might be more going on here than it looks.
Vol 3. CYMK
Someone stole Daughter's guns. That was ill-advised. Is someone trying to steal Son's stuff too? Daughter is convinced to join ZOMFU, and ZOMFU asks Son to investigate some thefts. A lot of things get hacked or broken, and someone gets hit in the head with a toaster
Vol 4. RBG
Son and Daughter continue to investigate thefts. There are new Bad Guys. Daughter continues her ZOMFU training. There are guns that shouldn't exist. A lot of stuff gets burned, bad guys get beat up, and someone just barely manages to get hit in the head with a toaster.