Mahou to Noroi to Hanataba to

While sorting through her mother's belongings, Mary discovers a letter addressed to someone she's never heard of. Upon reading it, she finds that it appears to be a love letter. Having seen a side of her mother she never knew, Mary uses the letter as a guide to find her mother's pen pal, Roy. His recounted memories reveal a side of her mother she never knew, a story of magic, curses, and love——