What older child hasn't resented the new baby? And hasn't wished for him or her to just GO AWAY? Every parent and child will recognize Harry's older brother's outbursts when Harry gets centre stage:

Throw Harry in the trash!
Stick Harry in the zoo!
Mail Harry to the moon!

But one day, when Harry is unusally quiet and his giggles and shrieks can't be heard around the house, his older brother realizes how much he misses him. Was Harry really mailed to the moon? In a delightful flight of fancy, the older sibling finds an imaginative way to accept and embrace that Harry's here to stay.