Following the catastrophic final jump of the Pillar, the last Dimensionaut is stranded in the furthest reaches of space, adrift on the wreckage of his former self. Before he can reclaim his mantle as protector of the Eververse, he must first overcome the demons that lurk within his own soul.

Reunited with their leader Grant McKay, the Anarchist League of Scientists dive deeper into the Onion than ever before. Now veterans of inter-dimensional travel, the team begins to realize how damaging their actions are on the fabric of reality.

Now, Hazel's fugitive family must risk everything to find a peaceful future in a harsh universe that values destruction over creation.