Jo returns to the UK to rescue the Porter family, who are being held ransom by their nine-year-old daughter. Princess Maddison is a terror, ruling with a heavy hand and throwing tantrums like a toddler to get her way. To make matters worse, seven-year-old Harry is quickly following in his sister's unruly footsteps. With both parents treading on eggshells, can Supernanny restore order -- or is this one battle of the wills that can't be won?