The sea can be a dangerous place for a turtle.

Yu is a loggerhead turtle who lost most of her flippers to a shark.

But as NTV reports, there’s a happy ending to this story.

When staff at the Hiwasa Sea Turtle Museum in western Japan found Yu five years ago, she was in bad shape.

Hiroki Tanaka was charged with caring for her.

Tanaka says loggerheads rely on their flippers, but Yu didn’t have enough power to flee predators.

He says it would have been tough for Yu to survive in the wild.

But Tanaka wanted Yu to be able to return to the sea.

He began to work with a maker of prosthetic limbs.

They started out by making a mold of Yu’s injured flippers.

They were able to get Yu to swim, but the prosthetic flippers were problematic.

Yu’s limbs became raw where the flippers were fixed to them.

Tanaka says they needed flippers that would protect Yu.

The team created 35 different prototypes over five years.

The prosthetic expert says they couldn’t talk with Yu, so it was hard to find the right balance of flexibility and strength.

Finally they found the correct mix with a sleeve.

It was a perfect fit for Yu.

It’s Yu’s big day—her debut at the aquarium.

Thanks to a remarkable team effort by prosthetic experts, material makers and marine biologists, Yu is back in the water where she belongs.