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 - and no one should have to deal with photos of their dad with the hashtags #viagraworks and #sexinyoursixties. Now they're selling the beloved family home and holding a 'house-cooling' party. When Effie receives only a last-minute 'anti-invitation', she decides to give it a miss.
Until 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.
Of course, nothing goes to plan. Not only does Effie bump into her ex-boyfriend (who she's very much not over), she can't find the dolls. And as she secretly clambers around dusty attics, hides under tables and mournfully eyes up the dessert table, she discovers unexpected truths about her family - and even about herself.
With time (and hiding places) running out, Effie starts to wonder if she'd be better off simply crashing the party. Perhaps that's the only way to find out what's really going on with her family...