Pingu is having trouble getting his sleep, but when he sees Pinga sleepwalking out through the bedroom door, he becomes fully awake indeed. Pinga walks right past Mum and Dad dozing on the sofa and up to the front door which she walks right into, without stopping or waking up. Pingu tip-toes past Mum and Dad and opens the door for Pinga. Once outside, Pinga continues to sleepwalk across the snow in the antartic night, with Pingu in hot pursuit.
Pingu tries to get in Pinga's way to stop her, but she just pushes him over. Pinga sleepwalks right into another penguin's igloo and out again. As Pingu apologises for intrusion, Pinga sleepwalks into their washing and a sheet falls ontop of her. At first, Pingu thinks she is a ghost, but then he stamps his flipper on one corner of the sheet and it falls off to reveal Pinga. Suddenly Pingu spots Pinga sleepwalking straight towards a sheer drop; quickly, Pingu borrows a nearby sledge, zooms ahead of Pinga and jumps across the drop. There he stretches himself across the gap as bridge for Pinga to cross safely. Pingu chases after Pinga on the sledge and follows her under a line of breaking icicles and up to a high pillar of ice. Pingu watches in horror as his little sister sleepwalks onto the edge of the column which crumbles under her weight. Luckily, the ledge lands behind the sledge and Pinga sleepwalks straight onto the sledge.
Quickly, Pingu sledges Pinga straight home and they arrive back at the igloo, just as dawn is breaking. Pingu sleepily helps Pinga into bed and then slumps exhausted into his own, but he does not sleep for very long. Soon Dad comes in, to wake them up; Pinga wakes up instantly, feeling very refreshed, but it takes several promptings for Dad to wake Pingu. Pingu walks heavy eyed up to the table and falls straight back to sleep in his chair, with his face in his breakfast.
- Pingu does not take the sledge back to its owners.
- Somehow, it takes Pingu the rest of the night to sledge Pinga home, when they only got to the column of ice in a matter of minutes before.