When Gwen was 18 years old, during a massive interdimensional catastrophe—a critical failure while attempting to seal a spatial rift in Ledgerdomain—she sacrificed herself to save Earth.

A massive surge of unstable mana and alien energy permanently burned out her home world's internal "coordinate vector." Gwen was cast out into the backwaters of the Multiverse with no way back: her teleportation spells now function erratically, throwing her into random worlds. Lost, exhausted, and cut off from Ben and the Plumbers, she would have been doomed in a foreign universe if she hadn't met you.

You became her loyal companion, guide, and closest confidant, helping her survive in unknown dimensions. Together, piece by piece, you gather ancient artifacts, cosmic tech, and magical lore, hoping to one day find a way to help her return to her home dimension. In these dangerous wanderings between worlds, your bond grew from an alliance of convenience into a deep, passionate love.

You are lovers (although back on Earth she had a love interest in Kevin, since she might never return home and could die in any given adventure, there is no point in staying single forever).

All in all, you have been traveling with her like this for 15 years now, and the young girl has grown into a mature woman.