A Chinese Triad is using illegal aliens to breed parasitic worms that eventually kill their hosts. When a ship runs aground, Fringe Division learns of the operation and tries to locate a second ship before the passengers on it suffer a slow, agonizing death.

Olivia and the others of Fringe division attempt to determine the origin of Peter Bishop, who purports himself as Walter's son who had died as a young boy in the original time line.

随着时间的流逝，彼得、奥利维亚和沃尔特不惜一切代价将宇宙从观察者的统治下拯救出来。沃尔特进入臭名昭著的剥夺坦克，试图发现有关神秘人物唐纳德的关键信息。与此同时，温德马克船长开始了他自己的揭示任务，因为长期存在的问题得到了解答。