After typing all that out, realized that was kinda long for the premise.

Summary
--The story is placed in the "real" world with some obvious differences. Massive light engulfs the planet, seven million are vaporized, moderately powerful fires across the planet, and a week long blackout. Power is restored to the world on the eigth day, and a week from then three million of the seven vaporized return to the earth.

--The vaporized that returned have been granted superhuman powers, each individual's power is based off of their subconscious desires & wants. So a super nosy person might have gained the power to read minds, a person who feels bound to their surroundings might have gained the power of flight, etc.

--The cause of the incident was caused by a multi-national government experiment on futuristic technology recovered from an attempted invasion from a Parallel Earth, similar to our own with an altered history. Said organization has formed an international secret military coalition known as "Legion" to hunt down, capture, kill & possibly recruit the superhumans. A few people's powers manifested shortly after the returned, others manifested over the three months, and SEVERAL have powers that are still dormant. 

--Storyline focuses on the world recovering, dealing with super-human powers, The Legion attempting to move in the shadows, and fix this situation, and also the looming threat of the parallel human earth actually managing a successful invasion of earth.