Lawrence's memory is accidentally erased by a gadget in Perry's lair before participating in a father-daughter race with Candace, so Perry operates a robot version of Lawrence to fill in for him. Meanwhile, Dr. Doofenshmirtz invents an opposite of glue named "Eulg," which breaks stuff apart rather than join it together. / Candace and Suzy try to get Phineas and Ferb to bust themselves, the boys build a replica of Niagara Falls so they can ride a barrel over it, Doofenshmirtz builds a device to increase his carbon footprint.