Shimajirou to Ehon no Kuni Shimajirou and the Country of the Picture Book
The story begins when Shimajiō and his friends go to the sea and find a picture book that Shimajirō had treasured in his childhood. When they hear a voice beckoning them from the book, they are drawn into the world of the book. There, they meet Puni-tan, and find a town of sweets in the middle of a forest. Shimajirō must find a way to return to his world.
[Source: Anime News Network]