The Doom Portals storyline is twelve adventures. There are two finale adventures and ten adventures with connections and teases for both finales. Four adventures are “designed” with good alignments in mind and four are designed with evil alignments in mind. Each adventure can be played as a standalone with suggested adventure hooks to usher the Party into the module. Adventures can be played based on their suggested alignments, or straight through, or some mixture. Moreover, the adventures have timeline and experience gaps to allow side, non-Doom Portal adventures in the hope it makes integration into standing games or other modules easier. Either or both finales can be played in any order, though The Islands of Insanity is the dominant plot-line.
The series has three optional entry points followed by two parallel tracks ("A" for Good-aligned parties; "B" for Evil-aligned parties) of three scenarios apiece, followed by three scenarios. Thus, although there are twelve scenarios in the series, a given party will play through only seven of them.