A catastrophic train derailment sends the city spiraling into chaos. But the derailment is just the beginning. A biological gas attack sees crash survivors collapsing and dying within minutes. And the sickness is rapidly spreading.

When five women take part in a corporate hiking retreat and only four come out on the other side, Federal Agents Aaron Falk and Carmen Cooper head deep into the Victorian mountain ranges to investigate in the hopes of finding their whistle-blowing informant, Alice Russell, alive.

When a terrorist attack hits Sydney releasing a highly contagious virus into the population, Detective Leyla Nassar must race across the city and find the culprits while the Deputy Premier Pamela Laird battles power hungry politicians eager to use the catastrophe for their own nefarious means.

When a pop-star cousin comes to stay, a family's once normal life changes drastically.

Thor is imprisoned on the other side of the universe and finds himself in a race against time to get back to Asgard to stop Ragnarok, the destruction of his home-world and the end of Asgardian civilization, at the hands of a powerful new threat, the ruthless Hela.