Atlantis (Phineas and Ferb)

During a trip to the beach, Phineas, Ferb, Isabella, Buford, Baljeet and Irving try to find the lost city of Atlantis which is located in the bottom of the ocean. Then Candace and Linda enter a sandcastle building contest when Candace found out that Jeremy is the judge. Meanwhile, Heinz Doofenshmirtz creates an army of plants.