Karan just wanted to have a vacation with his friends and the girl he really liked. But within a few hours, his life has turned from that of a shy and reclusive banker, to that of the savior of the galaxy. (I prefer this one, but I think from this point, you're gonna have to clearly explain how that happens?)
Less than five hours ago, the reclusive and introvert Karan was an ordinary twenty-something banker in Mumbai.
Now, he is collapsing the lungs of an alien’s human form just by thinking about it.
Karan came to realize that there are many technologically and spiritually advanced species in the galaxy. But in spite of all their advancements and progress, they cannot seem to live in harmony. They are at the brink of a war, and he has the capability to build a team that will stop the galactic destruction. (Instead of explaining this part, I would drop it completely, whether he is alone or has a team has no bearing on Karan)
Karan's perfect reality has turned out to be a manipulated version of the truth. The girl that he loves is an extra-terrestrial, and his best friend is with him only to do his job of protecting Karan. In different circumstances, he would have wanted nothing more than to see them on the same side. But right now, they represent his pain of being deceived, manipulated, and used, only because unknown to himself, Karan’s inheritance links him to a mythological tale, and gives him the telepathic powers of a demi-god. <This is a lot of information and hard to read. You have two separate points, I would stick to explaining Karan's emotions before the genetic inheritance.
Now Karan must make a choice, knowing that it has galactic consequences. If he chooses to listen to his heart and condemn the ones that lied to him and manipulated him, it would cause a galactic apocalypse which even the human would not survice. And if he chooses to ignore his emotions to try and save the galaxy, he will have to give up his life as he knows it, and he might not survive the monsters that even the gods are petrified of.
Either way, chances are that he would not see the end of it all. But not participating in the war would let him spend some time with his true loved ones, and be true to himself. It was the right decision to make.
Or so he thought. I don't mind this ending, but I wouldn't write it as an choice, but what he gives up in deciding to bury his head in the sand. <This makes me want to read it because the hero doesn't go gung-ho, which adds an interesting complex to the story, which I think you should focus on in the query, better explaining the deception that hurt him and the emotions at discovering the girl he likes is an alien...not even sure what those are. Revulsion? Dragoness did a great job of editing, so I'm not going to rewrite it, but I think we need to know exactly how he saves the galaxy...does he steal a pseudo nuclear weapons? what, instead of 'saving the galaxy, tell us what he does because then we might understand how a banker becomes saviour of the galaxy?
SIDDHI: VASITVA is a 100,000 word YA/fantasy novel with elements of science-fiction and Hindu mythology. <<<Will add another book comparison here>>>. It also has the mythology-reality bridge like the Shiva trilogy by Amish Tripathi.
I think you're on the right track, I like this better than the countdown method, but their some imaginative leaps that I have trouble making without understanding a little more. Hopefully this helps.