過重刺蝟小肥肥因為身體的脂肪太厚，在寒冬到來時，竟然一點都不覺得冷，本來要冬眠的他忽然失眠了。睡不著，他決定離開了家人獨自上路冒險。The curious little porcupine Pulky gets hit by insomnia – at the very time of his routine hibernation. He leaves his family behind and sets of for a voyage.