Orange paperback mystery with handwritten note

I lost a printed media item in Wilmington. It's a 6x9 inch paperback with an orange cover and a black title on the front; the spine is slightly creased from travel. I think I last had it yesterday around 3pm near the Riverwalk entrance on Front Street, right by the old brick fountain across from the Market Street coffee shop. Inside the front cover there's a blue ink note saying 'For Sam, keep reading' and there's a small coffee stain along the bottom edge. It's sentimental to me because it was a gift from my sister, and I really need to get it back.