Chapter One There was one thing Zoomi loved: parties. And there was one place Zoomi didn't want to be: Moo's party. Not because Zoomi didn't like Moo. In fact, Zoomi loved Moo. Moo was Zoomi's best friend. Which is exactly why Zoomi didn't want to be at his going away party. There were starcakes and a cloud house and dinosaur rides. But Zoomi would give up a hundred dinosaur rides if it meant Moo could stay.

"I can't stay," Moo said when Zoomi asked for the fifty-third time. They were eating starcakes while waiting for their turn to go down the rainbow mud slide. "We have a new home now. Three hours away." Zoomi didn't know much about hours, but three sounded like too many. And she could not think of anywhere better than Moo's cave, where he lived now. Except for maybe Doug's bubble palace. Or Izly's treetop home.

Or Zoomi's own invisible castle. But Moo's parents had found some other cave in some other place, far away from Zoomi. "Your turn," Moo said. He always let Zoomi go first. Zoomi went splat onto her furry stomach and did a slip-slide-swoosh down the rainbow mud. When she got up, her fur had turned every color of the rainbow. Moo went down next. His slippery scales made him go extra fast.

When he got to the bottom, his parents said it was time to go. The party was over. "Don't worry," Moo said when Zoomi started to cry. "This is our Tricky Turn-around! And you know what that means." Zoomi was crying so hard she only heard the last word Moo said. "It is mean!" she replied. "It is so mean that your parents are making you move away!" Moo tried again. "No, Zoomi, that's not what I said.

I said it's our Tricky Turnaround. We'll finally get our Happy Helpful Humans! And they'll get us! And then you'll go down the rainbow mud slide together." Zoomi wiped away some tears. How had she forgotten? Her Happy Helpful Human! She had been waiting her whole life for this! "I'm really going to get one?" Zoomi asked. "We both are," Moo said. Zoomi swallowed. Moo's Human was the luckiest. Moo's Human got to have Moo.

But first, Moo had to leave Zoomi. That was the sad part. There couldn't be a Tricky Turnaround and a Happy Helpful Human without the sad part. And the sad part was really, really sad. That's what made it so tricky.