The Miracle of Excalibur is the twelfth OVA of the anime and manga franchise Detective Conan. The plot is based on Gosho Aoyama's short story "Excalibur".

The next morning, Conan is still sleeping and Agasa's new message came from the phone talking about baseball. Agasa wants Conan to meet him at the Beika Park's baseball field so he could ask him something.

At the baseball field, Conan arrives. The Guts baseball team are making fun of Minae, the only girl who's the number 9 baseball player of the Guts team and Akira, the number 18 baseball player of the Trys team is going to be the pitcher and Minae is going to be the batter. Akira tells Minae just because they're childhood friends doesn't mean he'll go easy on her. Minae feels the same way. Akira throws the ball and Minae hits it but it went back to Akira. Minae starts running around the field but she's out. Minae got so depress to herself and she wishes she had more strength. When Minae is about to go back with the other team, she accidentally trips on something and it's a baseball bat stuck into the ground. Minae wonders what it is and the coach of the Guts baseball team reveals it's the legendary bat. It was a story about how Hideki Matsui, a baseball player, stabbed it into the ground. All the Guts players are interested and they take a look at the bat. The person who removes the bat will be granted a true baseball player's power. When Minae touches it, it gave her a shock. She started pulling it but she can't pull it out.

About the bat, Agasa dug a hole and the coach planted it in the ground which they were the ones who set it up. Agasa and the coach were old friends and Agasa accepted to help his problem. The coach wanted to somehow give courage to Minae.

While playing baseball, Minae is thinking about the legendary bat that's stuck into the ground and thinks about taking it out. When the ball is hit, Kenta calls the right field which is where Minae is and she didn't catch the ball because she was daydreaming about the legendary bat. Akira insults Minae that she is slow as ever. Akira actually hits it to the right field on purpose.

Kenta, a number 1 Guts baseball player, went to sit on the bench and got upset that the Guts are losing and he had enough. He blamed Minae for her mistake that she wasn't focusing the game. All the players suddenly make an argument to each other about that it wasn't Minae's fault. They also argue about who's better and who's not. Minae felt so down about it but the coach later cheers her up by telling her to stay strong and she needs to keep the team together.

Minae starts pulling the bat again and determines herself to stay strong. She failed after pulling the bat.

Conan realizes what Professor Agasa is doing: Agasa and the coach are trying to give Minae the courage by making her take out the bat. The coach knows that when Minae pulls the bat out of the ground, she will gain the courage. Agasa got the idea from King Arthur's legend. The one about pulling out the sword to become the king. Agasa mentions about that Kogoro had a bat Hideki Matsui used. He got it from the Nichiuri TV. Anyway, Conan asks Agasa what does he want from him and the the truth is Agasa put drugs that made the dirt hard around the bat and he wants Conan to spray it around the bat to make a soft dirt with the squirting model gun. If Agasa did, he look suspicious, and that's why he's counting on Conan. So he gave the squirting model gun to Conan. Another favor from Agasa is that he wants Conan to prevent anybody else from taking the bat out. The reason why he wants Conan to do it is because his fortune is heading down.

Kogoro appears and sees the bat stuck into the ground. He wonders if it's his bat. Conan asks what's he doing here and Kogoro answers that he came to see the bat which belongs to him or not. Haibara tells Kogoro that it's Hideki Matsui's legendary bat and Kogoro starts pulling it. Conan tells him to stop but Kogoro tells Conan to be quiet because he thinks it's his bat. Agasa tells Kogoro to calm down abd he wants to know his story. Kogoro said yesterday, he thought bragging about it at the drinking party to his college friends, so he brought his precious bat. However, when he woke up and saw it, his bat was switched. He was also wondering, so he retraced his steps from the drinking party. He remembered that he stood on the ground on the way home from the drinking party. He was drunk while swinging the bat. When he swings, he puts it on the ground and runs around the field. He got even more dizzy after running on the field. He doesn't remember really well after that. Then he definitely picked up the bat that was near the home plate, put it away in the case, and went home. Conan thinks it's most likely swapped when he was running around and wonders where did the bat go. Agasa mentions about the bat, he met the coach yesterday on the field. During his walk, he found the coach thinking. That's when he asked him for help about Minae. They tried thinking of an idea at the nearby café, but they went back home empty handed. Then Agasa remembered about King Arthur's legend when he got home. Agasa called the coach and he brought the bat. Agasa took the job of digging the hole. They met at 10 PM at the field. Then the coach came empty handed. He looked at the bat in Agasa's possession and told him that it was a bat he forgot on the bench when they met during the day. They planted that bat in the baseball field. The planted bat is most likely Kogoro's bat. However, the part about why the coach's bat being on the home plate has caught Conan's attention.

While Minae is pulling the bat, she is interrupted by Kogoro claiming that's his bat but Minae doesn't want to let him have it so Conan knocks out Kogoro with his stun gun wristwatch. Kogoro went to the bench and falls asleep. Conan tells Minae that he will guard the bat and Minae thanks Conan after hearing that.

Suddenly, a dog just appears at the bat where it's stuck to the ground, and sniffs it. Then the dog starts digging it. Conan tries to stop the dog from digging but stopped by Haibara instead. But Haibara said dig and the dog continues to dig. Conan said stop after that. Suddenly, the owner of the dog appears and apologizes because his dog loves tennis balls. As soon as the dog smells one, he goes after it. Agasa wonders why the dog digs the ground where the bat was stuck to it and there are no tennis balls. After the dog owner apologizes, he and his dog are just going to watch the baseball game.

Next, Ayumi, Mitsuhiko, and Genta, appears and they found the bat stuck to the ground. Genta is about to pull it up but stopped by Conan. They came here after looking at the treasure map they recently picked it up and they thought the bat might be the treasure. Haibara interrupts and tells the Detective Boys that the bat is the treasure that they're looking for. Again, she's been saying unnecessary things to make someone pull out the bat. Genta is about to pull but Conan stops again as he explains everything to Ayumi, Mitsuhiko, and Genta. As they learned it, they think Agasa is the one who made the treasure map but Agasa doesn't remember making a treasure map. Conan wonders who drew the map.

Minae is still trying her best to pull the bat but fails again. Akira asks Minae that what is she been up to. Minae tells Akira to be quiet and claims that if she takes the bat out, she's going to pulverize Akira's ball. Kenta knows that the bat won't give powers to Minae after pulling the bat and Akira agrees after hearing what Kenta says. Minae is still not giving up.

Later, the police detectives, Takagi and Chiba appears and they found the bat stuck to the ground. As Chiba is about to pull the bat, he is stopped by Conan using Kogoro's voice with the voice changing bowtie to give attention to Kogoro sleeping on the bench. Conan asks what are they doing. Takagi answers that last night, the jewel shopkeeper from Beika was attacked on the head by a thief when the shop was closed. While he was unconscious, valuable jewels were stolen. When Takagi and Chiba were investigating, they received a report about two suspicious people burying a bat in the field. They think those two are the thieves and they came to the baseball field to bury the weapon, so Takagi and Chiba came to the field to check. Haibara tells the police detectives that Agasa and the coach were the two suspicious people and Conan appears to tell Haibara to stop. Takagi and Chiba notice Conan recently. As Conan explains everything about the story giving Minae a courage by placing the bat so she could pull it to Takagi and Chiba, they understand and it wasn't the weapon they're looking for. Conan asks the police detectives about the jewel robbery case that it could have been a scam to get insurance money. Takagi doesn't think that would happen. The shopkeeper was hit on the occipital bone. Hitting there is possible alone, but it's too difficult. It's just that the shopkeeper has a clumsy little brother. His alibi just doesn't make sense.

Minae is going to do it again by pulling the bat and this time she's serious. As Minae starts pulling, Conan is thinking that the bat is somehow connected for sure and everything that occurred is connected to the bat. A jewel robbery case, a treasure map, a dog smelling the tennis ball, and the swapped bats. When Conan checks Kogoro's bat, it had strange marks on it, so he wants Chiba to inspect Kogoro's bat.

During the game, it is now in the 9th inning so Conan is about to use the model gun to squirt the ground but first he needs a little help from Haibara. Haibara is at the field so Conan went to her. When the batter hits the ball, it's going to hit Haibara so Conan pushes her out of the way but the ball hits on Conan's model gun. The drug liquid has been spilled. Conan asked Agasa for a spare but he doesn't have a spare. Now they cannot take the bat out.

During the game, the Guts lost again. Kenta argues with the other player but Minae made them calm down. Akira is ready to hit and Kenta is now the pitcher. Kenta throws the ball and Akira hits it. Kenta cried out, "Right!" Minae is in the right field and she finally caught the ball from touching the ground. It's out.

Haibara confronts Kenta that if he keeps acting cold to Minae, nothing will change. She wants Kenta to be true self to her.

Minae is still pulling the bat but she still can't pull it out until sudden, Kenta decides to help Minae for pulling the bat. Not just only Kenta and Minae but the rest of the Guts baseball players decided to help Minae too. When they work together, they successfully pulled the bat out of the ground.

According to the scoreboard, it says 3 - 1, and 2 outs. It's a chance for turnaround home run. Takagi receives a call from Chiba about the information of Kogoro's bat. Kogoro's bat has the shopkeeper's blood on and the shopkeeper's younger brother's fingerprints. Akira is about to throw the ball and Minae is ready to hit the ball with the legendary bat. Once Akira throws, Minae hits the ball and it went to the left field but it's foul. Minae cries over the bat that she broke. When she hits it, the handle of the bat broke off. The Guts baseball team tell Minae to never give up and Minae will try again. She tied the bat to her left hand with the white cloth and she is going to beat Akira in the baseball game. When she stands on the home plate, she begs Hideki Matsui and the baseball god to give her the strength. Suddenly the spirit of the hand touches Minae's helmet to give her good luck. Again, Akira throws the ball and Minae hits it. The ball went up in the air while the storm creates the thunders and breaks the pole. She successfully made a home run and runs around the field with the happy face. Akira got angry, throws the glove on the ground, and steps on it.