A month.
A month was all she had in the human world.
After Prince Adrien broke the mysterious Ladybug's heart, she had run off into a cave where no mermaid else would dare come near.
Whilst looking around the familiar cave, a dark figure appeared out of the shadows.
The golden-haired mermaid's deep blue eyes stared deeply into Ladybug's eyes. The mermaid offered her a month of time in the human world, in exchange for her to leave Prince Adrien alone.
Which, definitely wouldn't be a problem for her now.
The blue-eyed creature also mentioned if she could win the prince of the human world's heart, Ladybug would be able to revert back to a human or mermaid whenever she touched water. However, if she didn't win the prince's heart by sunset on the last day, she would never be able to come back to the human world, and would be imprisoned in the sea.
Deep in the sea, you weren't allowed to look at humans, or even go above the water. You had to hide whenever humans came by, as you couldn't risk getting spotted.
The thing with Ladybug, was that she was mysterious, and not to mention, rebellious. She wore a black and red polka-dotted mask which matched her black and red tail. Nobody had ever seen her without the mask; in fact, one mermaid named Alya Césaire, was so interested in the bluenette, that she created a blog dedicated to figuring out who she was.
Ladybug also refused to reveal her real name; Marinette Dupain-Cheng. She wanted to keep her identity a secret.
Her parents had been imprisoned thanks to the king, who abused his powers. They were thrown in the cellar for being a day late on a knight's order of bread. She worked on her own, exploring abandoned ships and looking for empty shelters.
So she came back, as Ladybug. She found a pair of earrings and a mask on an abandoned ship she had been staying in; this sparked the idea for her to become 'Ladybug'.
Now here she is. About to leave again, traveling to the human world.