Heritage

After the Sailor Wars against Galaxia Sailor Cosmos returned to her own era and continued her battle against Chaos... And Chaos kept winning and winning and winning. How? Why? Cosmos went to the Gates of Time and Space for answers.
Before the Gates were Guarded by Sailor Pluto Chaos breached them and altered the timeline to ensure that it would -- in the end -- win. Only the power of the White Moon stood in it's way successfully, but, even so, the White Moon fell.
The only viable solution that Cosmos could find was to re-weave the bonds that Chaos sundered and to that end she -- with the help of her daughter -- decided to start with Sailor Mars.
On Rei's seventeenth birthday ChibiUsa arranges for her to "accidentally" meet a man named Kumo Tenka.

Crossover with Donten ni Warau (Laughing Under the Clouds).