Patricia McKay should have known better than to think she'd get a peaceful vacation.

Her boss sends her to Seattle with a nice hotel and actual free time. What could go wrong? Everything, apparently, when Patricia visits an art exhibit in an old theater and stumbles across a set of mysterious numbers that don't make sense.

With puzzle-lover Levi Edelstein by her side, what starts as innocent curiosity quickly turns deadly. Dangerous strangers want a stolen diamond. An old woman harbors explosive secrets. And Patricia's quiet getaway becomes a race against time.

Can she crack the code before the killer strikes again?