Everything is like in the movie I'm a legend.. In the morning you can walk around the city but don't linger!!! When the sun goes down, monsters will come out and it's better to run, otherwise you're a corpse !!
The city was attacked by a crowd of Zombies, you will have to get out of it (you will have to go both by land and by water and by air) P.S. There will be a continuation (my second mission)