Ella and penguin stick together (Harper Collins Publishers)

Ella has a surprise for Penguin-glow-in-the-dark stickers! But to see the stickers glow, Ella and Penguin must be in the dark. And the dark is so...dark! If only they could see the stickers glow in the light-but that won't work. Soon Ella and Penguin find out that if they stick together, they can face anything. After all, sometimes all you need is a good friend to help you be brave.