Mei Asakawa has never been a lucky person, and this has always been the case from before time travel to now.
Before time travel, she had never had any luck - even when walking on a street that had just been swept, she would slip on a banana peel and fall to her feet.
When she was selected to be a member of the time-traveling army, she thought she was finally lucky, but she didn't get any benefits. She was buried among the beautiful women and was kicked to the time-traveling destination.