A fun-filled day of ice-skating takes a turn when Nature Cat's beloved hot cocoa Hug Mug mysteriously breaks. But wait Ronald's favorite Bug Mug breaks too. Who would want to break not one but TWO mugs? Hal thinks there is a mug breaker around! Will the gang track down the Mug Breaker? Or will Ronald and Nature Cat never be able to enjoy hot cocoa on a cold day again?