When Laurel went off to the small coeducational college in Michigan which had been her great-great-grandmother's alma mater, she expected it to be fun -- and it was. What she didn't know was that she would find herself up to the neck in a century old, unsolved murder mystery which was to give her the thrill of establishing the identity of the murdered man and his killer. The mystery theme is well-integrated and companions a satisfying modern college story of dates, term papers and strict house- mothers. There is not only the sinister black opal which Laurel unearths but also the exciting and sparkling diamond with which her One And Only ends the story. Maybe her solution will seem a trifle glib and maybe everything falls in place too smoothly, but no one will care for it is a nice, light entertaining tale with the virtue, highly to be prized, of not following an exact formula.