Goodnight, Mr. Knight

After years of revolving-door foster care, one home to another, Owen and Martha are suddenly moved to a house in Toronto, where Sister Charlotte comes to take care of them.

"When Sister Charlotte limped through the front door of our house, I shouldn’t have been surprised. But I was. Her face was lined, her skin grey, and her hair dead and stringy, as though she belonged in a coffin. She didn’t wear a nun’s white head-cover; her plain blue dress with black socks and flat black shoes was the nun uniform for the Sisters of Sorrows.
“The first thing she said, before even being introduced, was ‘What a relief. These stronger pills are a miracle. I’ll be back in shape in no time.’”

When Owen and Martha realize that the “pills” are being supplied by a mysterious Mr. Knight, and the house they are living in seems to be hidden within the Catholic system, they want to know why. Their investigations uncover multiple foster-care secrets, including the reason they are being hidden.