故事大纲：
冬冬的爷爷去世了。
爷爷去世的晚上，冬冬独自走进爷爷的房间，躺在爷爷的床上。突然间，床往下陷，吓得冬冬赶紧躲起来！床中间出现一只小象，小象的鼻子卷着一封信，是爷爷要给奶奶的信。爷爷与奶奶吵架，奶奶一走，就没再回来了。
信上地址只注明"大樱花树下"，邮差也不知道该将信送到哪里。为了完成爷爷的遗愿，冬冬决定带上小象（阿福），出去找奶奶。途中，她碰见了一直跟踪她的男邮差（阿呆），再发现另一个跟踪男邮差的女孩（阿若）。
阿呆是一个一直以来不曾送出过一封信的邮差，于是跟踪冬冬，希望冬冬帮助他完成送信的愿望。
阿若则一直等着阿呆的回信的邮差，于是跟踪了阿呆。
就这样，冬冬、阿福、阿呆以及阿若，踏上了寻找奶奶的旅途……
Synopsis:
Dong Dong’s grandpa has passed away.
Dong Dong sneaked into the room of her grandpa and lied on his old bed. Suddenly, the bed sank! An elephant appeared with a letter holding on its trunk. It was a letter that wished to be delivered to Dong Dong’s grandma. Her grandparents had a big argue and her grandma left the house. Since the letter only mentioned ‘Under a Big Cherry Tree’ on its address column, the postman has no idea on where should the letter send to. To complete the last wish from her grandpa, she started the journey to look for her grandma with the elephant. Her journey was then joined by a postman and a lady.
During their journey, they met a tiger, a helpless bird and Dong Dong’s grandpa. When they finally made to the place, they saw an old woman resting under a big Cherry Tree. Dong Dong raised the letter in her hand and ran to the old woman. The old woman raised her head and her eyes stopped at a little girl who was standing before her……