Nice people are asking: Cool cover, but what is it about?

Here is the wording from the back cover. (I didn’t write it)

Sudden Darkness
Margot Hovley
“Brothers and sisters, may I have your attention,” President Green said into the megaphone. I held my breath. What would he say next? At that moment, I wouldn’t have been surprised if he’d said the moon was scheduled to turn to blood next Tuesday night. “As you know, alarming events are unfolding. People are scared and confused. Life as we have known it will never be the same, it seems.”
The news has been filled with stories of tragedy and turmoil. But world events like the recent bombings in London seem far removed from eighteen-year-old Amélie Hatch’s quiet life in Zillah, Washington. She’s content with the predictable pattern of her life—school, friends, work. But when Amélie’s father leaves on a mysterious Church assignment, concerns escalate as the family is left with few answers.
Then, in the span of moments, Amélie’s world erupts in chaos. Terrorists have attacked the US power grid. There is no electricity. Vehicles have ceased working. The nuclear facility at nearby Hanford is compromised, and radiation may be flooding the area. Without the guidance of their father, Amélie’s family faces a monumental task at the request of the leaders of the Church: members of their stake have been asked to walk to Utah, where they will find safety in Zion.
Fleeing her home and the life she knows, Amélie sets off on the arduous journey toward the refuge of Utah. There is danger around every corner as the group faces gunfire, kidnapping, and new terrorist threats. And as she finds herself drawn to two very different young men, Amélie recognizes a more personal peril—she’s in danger of losing her heart.