Toki wo Kakeru Shoujo

Yoshiyama Mihane is a 3rd-grade high school student. She is a member of the photo club at her school. The day before her summer vacation, she smells a lavender scent in the science lab and she suddenly gains the ability to leap through time. Fukamachi Shohei is Mihane’s classmate. He actually came from the year 2122 and is a researcher. Shohei lost a drug that allows him to go back to 2122. In the meantime, Shohei hypnotizes those around him and lives as a high school student. However, as time goes by, Mihane and Shohei start to have feelings for each other.
~~ Adapted from the novel "The Girl Who Leapt Through Time" (時をかける少女) by Yasutaka Tsutsui (筒井 康隆).