Every Friday the 13th, 6th-grade genius Nate Bannister does three not-so-smart things to keep life interesting. This time, he taught a caterpillar to read, mailed a love letter, and super-sized his cat Proton before turning him invisible. Now Proton is on the loose, and Nate and his new friend Delphine must reverse the experiment before the cat crushes everything and everybody in town. As if th…