与地球上的家人道别后，尼可在太空中醒来，发现萨尔维勒号偏离了航线，部分年轻船员更是怀有异心。

船上气氛紧张，船员们整装探索一颗未知的星球。在地球这边，艾瑞克试图破译来自伪影号的一条线索。

尼可盲目飞行，并努力应对受损的舰船和蔓延的传染病。知名记者哈珀·葛莱斯缠着艾瑞克打探消息。

尼可因飞船故障而陷入沉睡，反复梦见此生最糟糕的一天。

探索神秘卫星时，萨夏试图与第二件外星来物进行第一类接触，尼可和凯丝打开天窗说亮话。

尼可争分夺秒拯救飞船和船员，并想起与凯丝第一次见面的情景。萨夏担心自己的精神状态正在恶化。

艾瑞克处理伪影号的新方法引发了惊人的事态和严重的后果。萨夏探求萨尔维勒号的防御信息。

萨尔维勒号展开穿过暗物质场的古怪之旅，船员们一路狂欢。萨夏瞄上威廉的弱点。艾瑞克收到悲痛的消息。

争夺飞船控制权的战斗进入白热化，萨夏的最终计划浮出水面。艾瑞克审问与伪影号近距离接触的哈珀。

萨尔维勒号终于抵达目的地，尼可和她的船员因星球表面上的所见而震惊不已。

Shock waves hit a Salvare struggling in the aftermath of an epic act of destruction. Niko questions William's judgement as Erik looks to the Achaia.

Venturing into the ring to negotiate with the Achaia, Niko sees the unimaginable. Cas risks everything by sending Iara on a mission. Jana stuns Erik.

Left behind but holding on, Niko and Cas each tangle with the Achaia in their own way. At the Salvare, the crew uncovers a key alien vulnerability.

Under suspicion for severing a lifeline, Iara now finds her life on the line. William discovers a surprise within. A habitable planet calls to Cas.

The new planet holds promise — and unexpected threats in the brush. The tables turn as Richard reaches out to Iara. The Achaia open up to Erik.

Alone at last, or not? Salvare's team faces a rough ride home — and a cautious reentry. Elsewhere, Erik tests Achaian tech, then asks for a favor.

Giving up isn't an option: Niko hatches a plan and spars with Richard. The chase is on when the crew tries to stand strong, and noises rattle nerves.

In a flash, Niko and Richard's world takes a terrifying turn as they wake up in a cold, cruel trap. On Earth, the team grapples with memory gaps.

Eager to go home by any means necessary, Niko and Richard head to a planet with an artifact. Erik and Cas go undercover, and William brokers a deal.

As the Achaia close in, the crew moves quickly to create a new weapon and save Earth. The time has come for the heroic to make the ultimate sacrifice.