Love Rerun

Sayaka is an "old maid" who's never had a boyfriend before, but has been hopelessly in love with her friend from university for 10 years. However, the night before she's about to go on a date with him, she finds herself waking up in her co-worker's house, who she hardly even knows?!? But it turns out he's actually her boyfriend, but Sayaka has no recollection of this due to a supposed head injury? But why would she date him?!? Did she give up on her past love, and is this co-worker really someone that she's head-over-heels in love with? And most importantly, will Sayaka really continue to date this mystery boyfriend?