SOLVED. Middle Grade novel: boy goes to dimension where every day is a year. [s]

[Madison]

A patron requested a book with the following details:
- She read it in fourth grade (she's probably about 11 now, so published in 2015ish or before)
- The cover has a green house on it
- The author "looks like a vampire" in his bio photo
- The book is about a boy who goes out a window into a magical alternate dimension
- For every day that passes in the alternate dimension, a year passes in the "real world"

please help!

[Tab]

Does your patron remember any of the other characters, like villains, friends, family, pets, etc?

[Madison]

Tab wrote: "Does your patron remember any of the other characters, like villains, friends, family, pets, etc?"

There is a mentor of sorts who brings the boy into the other dimension, but that's all she remembered.

[[deleted user]]

Was the dimension good, or more like a purgatory/negative place?

If it’s the latter, it could be The Thief of Always

[Madison]

R.S. wrote: "Was the dimension good, or more like a purgatory/negative place?

If it’s the latter, it could be The Thief of Always"

We think this is it! Thank you so much!

[Kris]

A very popular book. It's been requested and found 20 times in this group.