McDonald’s wants people who order Happy Meals to be happy. It’s right there in the name, after all. So when the fast food chain got wind of a petition by two potential Happy Meal customers asking it to stop putting plastic toys in the kids’ meal, McDonald’s decided to listen.

The petition was started by sisters Ella and Caitlin McEwan, who, at ages 9 and 7, fall squarely in the Happy Meal demographic. They had reached out to the Big Mac peddlers in the hopes of making their case directly, but when that failed, the little eco-warriors did not give up. Instead, they turned to change.org to issue their call to arms. In their petition, they explained that they were spurred to act when they learned in school about the harm that plastic does to wildlife and the environment.

“We like to go to eat at Burger King and McDonald’s, but children only play with the plastic toys they give us for a few minutes before they get thrown away and harm animals and pollute the sea,” the two wrote. “We want anything they give to us to be sustainable so we can protect the planet for us and for future generations.” As of Friday, the petition had over 399,000 signatures, with a goal of 500,000.

In a statement—or rather a tweet—McDonald’s explained that it is working on the issue. “In the UK over the next six months our Happy Meal promotions will include a mixture of board games, books and soft toys—which will see an almost 60% reduction in the number of hard plastic toys given away in comparison to the first half of the year.”

While that’s too late for any tie-in to The Lion King movie release, perhaps there will be a plastic-free Mulan Happy Meal in some kid’s future. It would be a step toward McDonald’s pledge to turn their Happy Meals green by 2025.