One-Shot-A Day of Romantic Time Travel

Marky was having a pieceful nap when all of sudden, a girl appeared in front of him-err correction, over him. After talking to the girl, he found out that she actually came from the future! As the girl explained her purpose of her return to the past, Marky found himself helping her to achieve her goal. And while doing so, they developed feelings for each other...
Later did they found out that their meeting was just for a day...