Latios and Latias are siblings, so one day Ash and Misty were in a water race contest competing each other and Ash Pokemon Totodile ,went the wrong way and Misty won the race contest and got toured around the city and learn the history of Latios and Latias connected to the city and how saved the city in the past.In the city there are two bad women trying to catch Latios and Latias with special jewel controls the city water and machine to control the city .Ash and his friends decide to get ice cream and noticed that Pikachu went to get some water cool down and saw a girl holding water for Pikachu ,then the girl stare at Ash and went away .The two bad women had special glasses to spot Latios and Latias in the group of people in the city .They spotted Latias and try to catch her ,but Ash saw her again and blocked the attack from the Pokemon the women had and told Pikachu to attack the two women, and Ash got away with the girl and Latias brought where his friends and waiting for him to go to the museum .They got inside the museum and learned more history of Latios and Latias connected to the machine controls the city and the ancient fossil Pokemon in the museum .Ash noticed the girl again and started to follow her , but lost her , then Latias reappeared and told Ash to follow her to special spot she hides and plays ,but Latios wasn't happy and started to attack Ash and Pikachu ,but Latias block Ash told her brother it was her friend .Ash and Latias started to play the swing and final show her true form to Ash and he got surprise from it .The other girl was Latias friend Bianca who Latias like to copy her.So Latios trusted Ash and show him sight seeing and Ash really liked that after ,he had to go because it was getting dark . Night time came the two women saw Latios ans Latias hiding spots and try to catch them and caught Latios ,and Soul Dew jewel and went to the museum to start the machine to control the city .Latias got away and was looking for Ash for help , then she finds Ash sleeping and wake him up and his friends wake up too and saw Latias true form as a Pokemon . Ash and Latias got to the museum to free Latios from the two bad women and the soul Dew was all dark and one of the women touch it and all the water was gone from the city. Latios and Latias worked together to save the city ,but Latios has give his life to save the city, and when Ash and his friends found Latias. Latias lost her brother and show sight seeing for one last time and transform to the new soul dew to save the city to have water again. I cry end of this movie.