MILLIE OF THE MANOR

Running an entire manor house falls to a twelve-year-old when her parents are unexpectedly called away in Millie of the Manor, and the book takes that responsibility seriously: household staff, a shrinking budget, and the daily logistics of keeping an old house going all get real page time alongside the mystery. At 208 pages, there's a steady rhythm to it, Millie solves one problem, a new complication shows up, and a hidden-passage, lost-treasure mystery runs underneath the whole thing without ever taking over completely.

This book trusts practical problem-solving to carry a story more than most middle-grade adventures do, and budgeting and managing people turn out to be genuinely interesting when a resourceful twelve-year-old is the one doing it. The manor itself rewards close attention, holding secrets that pay off for a reader who's actually been tracking the details rather than skimming for the next reveal. This is a strong pick for a kid who likes competent, in-charge protagonists more than rescued ones.