Rosie, the bird, and Lightning, the horse, were playing at the park, enjoying the sunny day. They had just finished a game of tag when Rosie noticed something strange about Lightning. He was acting restless, pacing back and forth and snorting.

"What's wrong, Lightning?" Rosie asked.

"I don't know, Rosie," Lightning replied. "I just feel like I need to run."

Before Rosie could reply, Lightning took off, galloping down the path. Rosie flapped her wings, trying to keep up. They ran past the playground, the pond, and the picnic area. Rosie called out to Lightning, but he didn't slow down.

As they neared the edge of the park, Rosie saw Lightning's eyes widen in fear. Suddenly, he turned sharply and ran back towards the park. Rosie followed him, and they ran past the playground again, this time heading towards the woods.

Lightning was running so fast that Rosie struggled to keep up. Suddenly, he disappeared from sight. Rosie flew up to get a better view, but she couldn't see him anywhere. She searched the park, but Lightning was nowhere to be found.

Rosie was worried. She knew that Lightning was a strong and fast horse, but he wasn't invincible. What if he had been hurt or lost?

She flew to the vet's office, hoping that Lightning might have gone there for help. But when she arrived, there was no sign of him. She searched the park again, but still no luck.

Rosie was starting to panic. She didn't know what to do or where to look. She needed help, and fast.