Dungeons & Dragons Set 2: Expert Rules

From the back of the box:

This is Set 2. Do not buy this set until you have Set 1.

This box contains all you need to continue the Adventure:

Endless hours of adventures. The D&D Expert Set for character levels 4-14, including more combat rules, magic spells, treasures, monsters and added rules for Wilderness adventures. Module X1, Isle of Dread. A combined wilderness and dungeon adventure on a remote island filled with savages and prehistoric monsters! All the dice you need - six different kinds included, with marker crayon.