Effie's still not over her parents splitting up a year ago. Her dad and his new girlfriend are posting their PDAs all over Instagram (complete with super-gross hashtags #viagraworks and #sexinyoursixties) and as if that wasn't bad enough, they're now selling the beloved family home. So when Effie receives a last-minute anti-invitation to their 'house-cooling' party, she decides to give it a miss.

Then she remembers her precious Russian dolls, safely tucked away up a chimney. She'll have to go back for them - but not as a guest. She'll just creep in, grab the dolls and make a swift exit. No one will know she was ever there.

But Effie can't find the dolls. And as she secretly clambers around dusty attics, hides under tables and tries to avoid bumping into her ex-boyfriend (who she's very much not over), she discovers unexpected truths about her family - and even about herself.

With time (and hiding places) running out, Effie starts to wonder if the only way to find out what's really going on with her family is to simply crash the party . . .