When Cal wakes with a life-threatening fever, Grace worries it's a side-effect of his experimental cancer treatment, but Michaela and Ben suspect Cal's condition may be related to a mysterious passenger from Flight 828. As Cal's situation worsens, Ben and Michaela attempt to track down the now-missing passenger.

With the detained passengers secretly moved and subjected to painful experimentation - and Cal's health directly linked to them - Ben takes advantage of an old friend to find out where the passengers were taken. Meanwhile, a mysterious new version of the calling pulls Michaela into a murder investigation that has deep personal ramifications for her.

Ben forms an unlikely partnership with Vance in a high-stakes race to locate the missing passengers of Flight 828. Meanwhile, Michaela helps a suicidal passenger who believes he is the Angel of Death, and Cal goes back to school, navigating both his unwanted celebrity and his former friends, who are all now 16 years old.

When Ben and Michaela put everything on the line to save the other missing passengers, the mission goes horribly awry and not everyone makes it out alive. The devastating result pushes Ben and Grace to a traumatic brink, while pulling Michaela and Jared dangerously close together.

Michaela's mystifying, next-level calling launches her on a mission that brings her relationship with Jared to a head. Determined to protect his family, Ben explores an alternate meaning to Michaela's calling that leads him to a new alliance and a powerful new adversary. Cal's struggle with Ben's absence from home forces the Stones into an agonizing confrontation that could alter the family's fabric forever.

After finding another dead body, Michaela and Jared try to track down a serial killer. Cal goes on a date. Zeke faces old demons.

An ominous Calling shakes up Michaela and Zeke’s party. Cal and Ben receive devastating news. Michaela, Saanvi and Eagan look for the Omega Sapphire.

死期临近，呼召开始对卡尔造成影响。小组发出求救。熟悉的面孔在意想不到的地方带来希望。

萨维在病人身上测试理论，而乘客们争分夺秒地解决呼召。伊根做出令人意想不到的举动。米凯拉面对严酷的事实。

所有的迹象都指向地球的尽头，这促使斯通一家和乘客们一起努力，在时间耗尽前破解神秘线索。