Singularity

Identical twins Barry and Harry Krasner are house-sitting at their great-uncle's Midwest farm.  It's peaceful at first, but soon they realize there's something about the farmhouse that makes locals stay far away.  The twins are sure that the locked shed out back is their reason why – but what they find there is more shocking than anything they could have imagined.William Sleator (1945–2011) was the author of numerous science fiction books for children and young adults, including Interstellar Pig, House of Stairs, and Blackbriar.