Nine-year-old Sumac Lottery is not at all pleased when her estranged grandfather arrives in Toronto from the Yukon for an undetermined amount of time. The old man just doesn’t appreciate or fit into Camelottery, the 32-room home Sumac shares with her six siblings, four parents, and various pets – never mind that Sumac is the one who has to give up her room and act as his personal guide. Sumac takes it upon herself to make everything right again by trying to convince her family that “Grumps,” who is afflicted by steadily worsening dementia, should move into an assisted-living residence.

Readers will be hard-pressed to find a more diverse family in fiction. The Lotterys (who take their name after winning a jackpot) are headed by two same-sex couples representing four cultures – the dads are Canadian and Indian, the moms Mohawk and Jamaican – and the mix of adopted and biological children are of myriad racial backgrounds, with a few of them dealing with various issues, from gender identity to developmental delay.

The youngest of eight children, author Emma Donoghue certainly knows a thing or two about large broods, and her middle-grade debut is a tribute to the modern family. But in creating a family that embodies so many topical realities for readers to identify with, Donoghue runs the risk of rendering her characters strangely unreal. This issue is compounded by the Lotterys’s idealistic do-gooding and cutesy “Lottery-speak,” which is followed by explanations that break up the flow.

The conservative, curmudgeonly grandfather is a well-played counterbalance to the “hippy-dippy” Lotterys, continually questioning the family’s choices and counting down the days he has to live with them. His story – forced into a new home, city, and lifestyle so unlike his own, all while “losing his marbles” – is moving and endearing. The story’s quieter moments speak volumes about intergenerational relationships, familial duty, and mutual acceptance and adaptation. It is in these less showy areas that The Lotterys Plus One trades idealism for realism, and truly shines.