Solar flare brings civilization to its knees

My story is about a family consisting of 4 characters
Oscar(dad),  Strong, quick thinking, observant
Stephanie(mom), Care giver, loving
David(son) US veteran, strong, quick thinking
perla(daughter) quick learner, resilient, observant
My theme is suspense and fiction.

Beginning; My characters will be situated in a rural area in montana US, they are enjoying a meal together while watching tv when suddenly the tv is interrupted by an emergency message from the country and it says that there is a solar flare coming to Earth in 8 minutes and of intensity never observed before. This intensity of charged particles will destroy most electronics on earth including satellites, cell phones, cell phone towers, generators and cars etc. This catastrophic event will leave civilization to a stop and people will now have to prepare to live without the help of the government. Moments after the message the tv fries as the lights go off and the water stops running. They are now on their own.

Middle; Suddenly the realization kicks in and they are now terrified of this new situation. They must rush for the city and gather all the supplies they need before everything runs out.  As they arrive in the city Panic is unmeasurable fear is everywhere the chaos ensues until gangs start racing and shooting anyone that tries to take anything from the supplies People are fighting inside the stores with a few cans of food are left. They take what they can and rush home luckily. They are attacked on the way back by a group of survivors trying to steal what little they managed to find. The situation escalates and Oscar and David are forced to fight the survivors for the safety of their family, the fight ends by them killing the two survivors  but with Oscar badly injured. Oscar sadly dies due to his wounds and now it’s David’s duty to protect his mother and sister and survive.
End;  David must put to use his experience as a soldier to survive in this new hostile environment surviving off the land and fighting off groups of people that want their stuff. This continues for 6 years until Stephanie is bitten by an animal and her wound begins to become infected David must make a hard decision either he amputates his mother arm or he ventures into the city that had become a wasteland to steal antibiotics from a gang that now roams there.
He ventures into the city he is caught by some gang members and leading to an all out gun fight David leaves victorios, as he returns home he is brought with devastating news that his mother has succumbed as well. Full of grief and regret he promises to his mother and father that he will keep his little sister alive no matter the cost. He proceeds to teach Perla to hunt, skin animals, purify water and absolutely everything necessary so they can live. They have now adapted to this new world and the concept of a cell phone and cities become a distant memory