Kate, Mike and Carlos go on another trip to Bodega Bay near San Francisco, where more than a year ago they found a pirate's old treasure map. An incredibly exciting and dangerous adventure awaits them as they follow a mysterious clue and go on a treasure hunt to find a lost treasure from centuries ago. The GREEN APPLE series is composed of illustrated graded readers. The readers are graded into three levels — Starter, Step 1 and Step 2 — according to structural and lexical criteria, as well as by choice of subject matter.