Robbie is four when his mother takes him to the beach for the day. His father has to work, but they'll have fun, just the two of them, she promises. There's a cooler with a picnic lunch, a thermos of lemonade for Robbie and a thermos of lemonade for Mum so they don't get each other's germs. Mum rubs sunscreen on him and tells him not to go past the rocks on that side or the life-guard stand on the other side. And don't go into the water without her! She's tired from the drive to the beach and needs to close her eyes for a while.
While Mum takes a nap, Robbie makes a new friend, and they build a sand-castle together until the other boy's mum calls him for lunch. He's hungry too, but Mum is still sleeping and he knows she doesn't like it when he wakes her. If it's time for that other boy's lunch, it must be time for his lunch, he decides with his rumbling tummy to back him up. He eats one of the sandwiches with a big pickle and a frosted cupcake, and drinks the rest of his lemonade.
He rejoins the other boy at their sand-castle, and they play invasion of the killer shark monsters until the other mum calls his friend to go home. Robbie's mum is still stretched out on the beach blanket, and Robbie sighs. He's thirsty. His lemonade is gone, but there's still some left in Mum's thermos. He thinks very hard about germs, and arrives at the conclusion that if he uses the cup from his thermos, it should be okay. And if he does get any germs, Daddy is a doctor and he can fix it anyway, and besides, Robbie's really thirsty. And hungry. He takes another sandwich from the cooler.
Can lemonade go bad, or did she use too many lemons? It's bitter, kind of, and burns when he swallows it. Robbie eats the sandwich and haltingly drinks the sour lemonade. Except for building the sand-castle, he hasn't had very much fun today. He's so hot...his skin is bright pink, how silly that looks. He wonders if the pink will wash off. It would be awful for it to stay that way---pink is for girls. Maybe it would be okay to go into the water just a little bit to rinse off the pink? Its sunlit ripples glitter like ice cubes in a cool glass of water.
The waves beckon him, and with one last glance at Mum, Robbie heads toward the bright blue ocean.