The show focused on a 4-foot-tall (1.2 m), purple alien from the Horsehead Nebula named Widget who could shapeshift (usually by spinning like a top into different forms, in early episodes he seems to still be getting used to his power). He and a group of young, human friends; brothers, Kevin, Brian and their teenage sister Kristine, would go through a number of adventures to protect the natural environment from those who wish to plunder or harm it. Later on they were joined by (fellow shapeshifter) Half-Pint, Widget's mischievous, overly-curious, hyperactive cousin. Widget is frequently accompanied by the Mega Brain, an extremely intelligent but somewhat clumsy being who appears as a floating head (with a transparent cranium) and floating hands.