Tenkei no Arimaria

Tenkei no Arimaria summary:

Japan: the Gambler's Paradise! The rich and beautiful Maria is well-known as a legendary gambler who will take on any challenge, no matter how unreasonable or impossible! But what happens when she meets a lowly slave who solves her riddle..? Twist after twist! So tense you'll forget to breathe! This MangaBox-exclusive five part gambling story will leave you aching for more! Prequel: Once Upon a Time