Bi Bi and her grandfather visited Thu Le Park to enjoy a day out. They discovered a plastic fishing game at the park, where schools of plastic fish floated in a tank filled with water. After purchasing tickets, they eagerly engaged in the fishing activity.

As they fished, a strong gust of wind enveloped them. Suddenly, they found themselves transported to the middle of an ocean. The fishing rod extended magically with a long line and a massive hook. Bi Bi's grandfather exclaimed:

Let's commence, my dear!

Both the grandfather and granddaughter focused on their fishing.

They successfully hooked a colossal tuna and shortly after, a red snapper. A tiny fish was caught on the hook, prompting Bi Bi to remark:

It's so adorable, let's release it, sir!

The duo gently removed the fish from the hook and placed it back in the water. After a brief struggle, the fish swam around, bidding farewell to the couple before diving into the deep sea.

After some time, the end of the fishing line became heavy, and the boat was pulled by a powerful fish. "Whoa," he exclaimed as he tumbled into the sea, still clutching the fishing rod. The fish dragged him away until the boat came to a halt. Bi Bi cried out to him:

Sir, let go of the fishing rod!

Struggling, he tried to release the fishing rod, but his sleeve got stuck. Eventually, he managed to pull out a small knife and cut the fishing line. The fish escaped, and he swam back towards the boat.

Suddenly, he was startled and shouted, "Oh, what's touching my leg!" It turned out that a massive dolphin had approached, offering assistance. The dolphin carried him back to the boat on its back.

Bi Bi was astonished to find her grandfather sitting on something black resembling a boat. The two joyously called out to each other. The dolphin spouted a jet of water into the sky, seemingly greeting Bi Bi. Recognizing the dolphin from a performance in Tuan Chau, Bi Bi was further surprised when the dolphin sprayed water, wetting her shirt. The dolphin came close to the boat, and the grandfather struggled to climb back on board. The dolphin then left, shooting three high jets of water into the air, appearing elated.

Undeterred, the two continued their fishing. Bi Bi pulled up the fishing rod and exclaimed:

I've caught another fish!

To her amazement, it was a plastic fish. She questioned, "Oh, plastic fish! Where did the sea go?" It turned out that Bi Bi had imagined the vast ocean while sitting with her grandfather by the plastic tank, fishing for plastic fish.