Before I begin, let me give you a few links about this drama.
The english name for Proposal Daisakusen is Operation Love. Simply put, the whole drama is about an operation of love. Its not an operation where you have to go for surgery of course, but a mission rather, to get love. This drama is 11 episodes long and it has my favourite Japanese actor Yamapi inside. I liked the actor (not in a gay way) since I watched Kurosagi, another drama he starred in about swindling swindlers.
Proposal Daisakusen is about this young man named Iwase Ken who is currently about to attend a wedding ceremony. The bride is the person he loves, but because he never once confessed to her, the bride went to another guy. The sad thing is, the bride is in love with Ken all the while, just that the Ken in the past does not realize it.
A slideshow with many photos is shown and after seeing that Ken is feeling regretful, a fairy appears (a guy fairy..) and grants him a chance to go back to the past and change things. The thing is that he can only go into the timeframe of the photo taken.(the photo in the slideshow). And, he will come back to the present when the photo is taken again.
Thus begins his journey into the past. Will Iwase Ken confess in the end? Will he manage to change things and end up marrying his childhood sweetheart? Or will he give up in the middle and watch the 2 get married? Watch Proposal Daisakusen now.