A toxic gas invades an entire city, and the main character, Lee, must find a way to save his family and himself. The gas is released by a former laboratory employee who was fired and wanted to take revenge on the city.
Lee and his family try to find a safe place, but the gas is spreading quickly. They eventually reach the roof of a building, where they use a gas mask and plastic bags to protect themselves. However, they soon realize that the masks will only last for 15 minutes, and they must find a way to escape the city.
Lee, who is an experienced climber, decides to climb the building to open the door to the roof for his family. He also comes up with a plan to create a bridge to reach the next building, using ropes and weights.
Meanwhile, Lee's family is trying to find a way to signal for help. They use a microphone and speakers to sing, which eventually attracts the attention of a rescue helicopter.
However, the helicopter can only take 20 people, and Lee decides to stay behind with a friend. They try to find another way to escape, using a drone to create a live broadcast and ask for help.
The broadcast is successful, and many people team up to help the boys. They use drones to carry a rope to the other side of the building and attach it to a pipe, allowing the boys to slide down to safety.
In the end, the boys are rescued by a helicopter and reunited with Lee's family. The movie ends with the gas being neutralized by rain, and Lee asking his crush, You, out on a date.
Here are the key facts extracted from the text:
1. A toxic gas invades an entire city.
2. The main character, Lee, is a climber who lives with his parents.
3. Lee's family attends his mother's birthday party, where he meets a girl named Yu.
4. Lee is still in love with Yu.
5. A toxic gas starts spreading through the city, and Lee's family tries to find a way to escape.
6. The gas is spreading quickly, and people are trying to find shelter.
7. Lee's family tries to get to the roof, but the door is locked.
8. Lee decides to climb the building to open the door for his family.
9. Lee successfully opens the door and lets his family in.
10. A rescue helicopter arrives, but it can only take 20 people.
11. Lee decides to stay behind with Yu while his family is rescued.
12. The gas is rising, and Lee and Yu need to find a way to escape.
13. They use gas masks and plastic bags to protect themselves and try to find a higher building.
14. Lee's family arrives at a safe zone and tries to find a way to rescue Lee and Yu.
15. A group of students is trapped in a classroom, and Lee tries to help them escape.
16. The students use mannequins to create an arrow to signal for help.
17. A helicopter arrives to rescue the students, but Lee and Yu are still trapped.
18. Lee and Yu try to find a way to escape by using a rope to slide to a nearby building.
19. The rope breaks, but they manage to fall onto a crane.
20. A helicopter rescues Lee and Yu and takes them to the safe area.
21. Lee is reunited with his family, and he asks Yu out on a date.
22. It starts raining, and the gas is washed away.