Relationship
On his very first day traveling, Ash encountered a young redhead named Misty. After fishing him out of a river, Ash, with his wounded Pikachu, insisted that he borrow Misty's bike. He rode off on it, promising to return it. However, Pikachu ended up destroying the bike with a Thunder Shock attack. Instead of aiding to the bike, Ash rushed his injured Pikachu to the Pokémon Center in Viridian City, where Misty tailed him once she discovered her mangled bike.Misty and Ash ended up traveling together and she insisted it was specifically because of Ash destroying her bike. She also claimed she wouldn't leave until Ash repaid her. Although Ash and her bickered continuously, Misty began developing a fondness, and possibly attraction, for Ash. This hindered why she had decided to tag along and the reason faded in and out.
Their first stop was in Pewter City. Misty urged Ash to use some of her Water Pokémon against the Gym Leader's Rock types, but he refused. Insulted, Misty did not participate in watching his first battle, which is ultimately lost after he battled with Pikachu.
The Pewter Gym Leader, Brock, came off to Ash as a rather coldhearted and distant guy. Despondent for losing against the first Gym Leader, he ran into a man named Flint, who helped recharge Pikachu with a special device that would power-up the Electric mouse. The man also showed Ash where Brock lived, and Ash was shocked to witness Brock taking care of his nine brothers and sisters in a motherly fashion. Apparently, there was more to Brock than Ash thought.
Ash had a rematch with Brock (which Misty watched), and using the water sprinklers on the ceiling as a strategy, he was successful at beating Brock and earning his very first badge. Flint, the man Ash met earlier, revealed himself as the long lost father of Brock and agreed to reclaim the title of Gym Leader and take care of his younger children. Though bitter, Brock used this as an opportunity to travel and decided to come along with Ash on his journey. Misty reluctantly followed, still claiming she wanted her bike.
Since Ash met the two, the three have been through some rather incredible journeys and events. The first of these would be their experience in Mount Moon, where they witness a Clefairy and Clefable ceremony with the Moon Stone.
Misty and Brock watched Ash catch all his Pokémon in Kanto; they even witnessed him having to goodbye to a few. Staying by his side, they helped him through his Gym battles, always offering advice when Ash was willing to take it.
Their journey through Kanto takes almost an entire year. Through that time we watched them grow as characters and as friends. One of their most memorable experiences occurred in Mewtwo Strikes Back on New Island, where they witnessed the horrors of cloning and the darkness humans bring into the world through their unfortunate need to control other beings.
During the Indigo League, Misty and Brock cheered for Ash in each and every round. When he lost, they were there to comfort him, and it was their friendship and support that made him look towards the future and become more determined to be the World's Greatest Pokémon Master.
When Brock departed from the group for a short amount of time, Misty and Ash continued traveling and met up with a boy named Tracey, a Pokémon Watcher. Although Misty and Ash became very good friends with Tracey, their bond with him was nowhere as strong as their bond with Brock. Brock eventually rejoined the group before Ash decided to travel in the Johto Region.
Reunited, the three again went through exciting and thrilling adventures. Brock and Misty again cheered for Ash as he battled for his eight badges in the new region. After a long and strenuous journey, Ash made it to the Johto League, accomplishing more than in the Indigo. He made it into the Top 8, even managing to beat Gary Oak, his longtime rival.
After the Johto League, the three decided to go back to Pallet Town to visit Ash's mother. On the way, they stopped in Viridian City. At the Pokémon Center, Nurse Joy told Misty she had a message from her sisters to call them back as soon as possible. She did so, and Daisy told her that she needed to come to Cerulean City to take over the Gym (apparently they won an around-the-world tour). Misty objected to this, but they gave her no choice.
Nurse Joy, the very same that treated Ash's Pikachu at the beginning of his journey, approached the trio and revealed a shiny red bike. She told them it was Misty's, and she had fixed it up for her. Smiling, Ash told Misty that the bike would come in handy and she could get to Cerulean City even quicker, oblivious to the amount of pain Misty was already enduring.
After taking off to collect her thoughts, Misty joined up with Ash and Brock in the city, and the three headed off into the outskirts. Misty explained to Ash and Brock how much she was going to miss them and how their adventures together were the most remarkable she'd ever experienced. Ash and Brock agreed.
At a three-way intersection on a path, Misty began to say goodbye to her two friends. At the very last moment, however, Brock revealed in a fit of revelation that he, too, had to go back home for a short amount of time. Ash and Misty gaped, but Misty understood how Brock forgot on account of not wanting to truly leave.
Misty and Brock said a quick goodbye to Ash, leaving him to mull over the events he went through with his two closest friends. However, playfully, Misty and Brock snuck up behind Ash, their unique style of giving one true and final goodbye. Brock handed Ash a small package meal with a fork and a knife, while Misty presents a pink handkerchief. After thanking them, Ash, Misty and Brock each take their individual paths back to their hometowns.
Since then, Brock and Ash reunited and traveled through Hoenn with their new companions, May and Max. Misty appeared The Princess and the Togepi and A Togepi Mirage for a cameo appearance and later on, showed up again in The Scheme Team and The Right Place and the Right Mime! Even after the Hoenn series ended, Brock joins Ash again for his adventures through Sinnoh.