This is solid middle-grade fantasy with a genuinely creative hook—a time-traveling house and a memory-stealing boogeyman make for an atmospheric, eerie read that doesn't cross into truly scary territory.

The imaginative world-building is the star here, with the Calendar House and Horatio's ability to move through time creating real narrative tension. The emotional arc works too: Amelia goes from resentful outsider to protective cousin, learning to value family connections through nearly losing them.

The manipulation dynamic—an older entity befriending a 10-year-old to use her—is handled appropriately (it's clearly villainous, and Amelia recognizes it and fights back), but it might feel uncomfortable for some families. One reviewer found it 'a little too creepy' for their taste, which is fair.

The protagonist's initial sulkiness is necessary for the plot but might turn off some readers early on. Still, School Library Journal called it 'a solid middle grade fantasy with an intriguing setting and a relatable protagonist,' and that feels right. It's well-written, engaging, and asks interesting questions about memory and family—just not a must-read that will blow everyone away.