When Milo’s family moves to a new city, he vows to officially retire from having fun. So he stays inside for days while his little sister, Georgie, yearns to explore the new neighborhood. Finally, Milo ties Georgie to the end of a ball of yarn so she can go out, on one condition: she has to come home when he tugs the string twice. But one day, Georgie isn’t at the end of the string. Which means Milo might just have to step outside and discover everything he’s been missing.