Where's the Heat Thief?

In the picture book "Where's the Heat Thief?" by Kwak Min-soo, Granny Bear struggles with the cold winter and heats her house, but she notices the warmth disappearing. Her friend Momo the cat, who understands that heat naturally moves from warmer areas to cooler ones, searches the house to discover what is stealing the heat. Together they explore the science of heat transfer, learning that no actual thief is taking the warmth but that heat escapes to colder spaces.