Doraemon is a blue cat-shaped robot who came from the future. His best friend is Nobi Nobita, a 10-year-old boy who is in the same class as Minamoto Shizuka. One day, Doraemon, Nobita and Shizuka are walking along the street. Two of their friends, Gouda Takeshi, nicknamed Gian, and Honekawa Suneo, happen to meet the trio and show them the fish they caught at a nearby river. Doraemon and Nobita return to the Nobis' Residence where they live. Asking his mother, Tamako, over lunch if Nobita could go to fishing, she does not allow, as Nobita is clumsy and could easily fall into the river.
Doraemon and Nobita return to their room, and it is then that Doraemon realized that he could use a gadget from his fourth-dimensional pocket to do so. He takes out the Mobile Fishing Lake and selects a section of water. Whistling to the same tune from the beginning, he then takes out a pair of fishing rods and magic gloves. As for the fish that is caught, he uses a fish spray to allow them to swim in the air. Nobita catches a fish Gian is also catching. He and Doraemon freak out at the sight of Gian, who is fishing along the river with Suneo, and fold the Mobile Fishing Lake back.
Doraemon changes the section to the middle of a sea, and saves Nobita from drowning when he falls into it. He takes out a pair of scuba diving goggles for Nobita and they dive underwater. Later, they encounter a shark and swim for their lives. They swim back to Nobita's room, but the shark catches up with them and they struggle to fold the Mobile Fishing Lake back.
Doraemon changes the section to a hot spring. However, when Nobita and Doraemon jump into the spring, they drown and end up in Shizuka's bath tub, where she is disturbed while having a shower.
- Mobile Fishing Lake
- Fishing Rod
- Magic Glove
- Fish Spray
- Scuba Diving Goggles
- In the 1979 version, Shizuka has black hair, perhaps the only episode in the 1979 that has her with black hair instead of brown. Also, Gian's voice sounds a bit different than the rest of the 1979 episodes. Additionally, Nobita's room's door had alphabet letters instead of blue and pink dots, and it's one of the first 1979 episodes ever produced, making it a "pilot" episode for the 1979 anime.