Isabella and Riley from Canmore, Alberta, present their "Compawst Bin" a rugged compost bin designed to keep bears out. Connor and Spencer from Sudbury, Ontario, present their new "Biodegradable Plastic." They hope their invention will help reduce the number of plastic grocery bags in landfill sites. Riley and Isabella lead Team Edison against Spencer, Connor and Team Einstein in the Invent-Off Challenge to see who can create the best Pet Habitat.