Broken Date is a novella written by R. L. Stine. It was first published in 1991.
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Jamie and Tom have been going out since junior high. They are planning to graduate from high school and attend college together. Everything's perfect until Tom breaks a date--and all the horror begins. What has happened to Tom? To Jamie's horror, the boy she loves is stalking her and making threats. Now, there's nowhere Jamie can hide.