"If you don't know the source, be a paranoid bastard and look for one. Treat it like an enemy attack if you have to. If nothing else, it'll at least get you doing something."

Nagi glaaaares. "He does, and that's not one of them."

"He did?" That really sets Nagi back a bit. But other-Nagi wouldn't have known that the thing with Mamoru would be bad. And... "Did he ever do anything more about the house thing besides prank you guys?"