Jessie is a young, bold teenager, born in Salinas, California but moved to Grants Pass, Jessie had hard times making friends. His mother, Kristen asked him to go on a vacation to Saagen Town, Michigan to compete in the combat tournament known as Tournament Kamen Rider. Jessie was reluctant at first to go, but with the added support of his mom and dad, Clarence, Jessie worked up the courage to get on the plane and go to Saagen Town, Michigan.
Once there, he ran as fast as he could to Grand Central, where the official Rider Belt distribution was taking place. There weren't that many rider belts left, but he got the one that suited him: The ShadowMoon KingStone! After he had filled out the form, the ShadowMoon KingStone snapped onto his waist and disappeared until needed. He saw everybody run from something, so he went to check it out on Battle Hopper, his Rider-Cycle.
After he dismounted from the bike at his destination , he saw a spider-like fangaia suck the energy out of a person with invisible fangs. Jessie summoned his new ShadowMoon KingStone to his waist and called out the phrase, "SHADOW HENSHIN! He then struck a henshin pose similar to Kamen Rider BLACK RX. The kingstone flashed all around his body and ShadowMoon's armor flashed onto his body. after the transformation, his green eyes flashed and called out as his opening statement, "THE PRINCE OF DARKNESS, KAMEN RIDER SHADOWMOON!" He then started to fight the fangaia.
After a Shadow-Fist and Shadow Rider Kick combo, the fangaia was destroyed. Jessie changed back into human form to check out what the other riders were doing. The Godfather of the tournament, Jack Ryker was in the room filled with Kamen Riders participating in the tournament, wishing them all good luck. Jessie then bumped into Chad 'Phoenix' Leiter/Kamen Rider Kiva. After they talked a while, they extended their goodbyes. Jessie then rode into the woods to take a shortcut to the tournament's first stage, but he was deterred by a man named MONARCH, who was Kamen Rider Stronger. After they henshined, they had a big brawl. Jessie was the winner of that bout, and rode off to help Nero's team.
Jessie then changed into ShadowMoon to help Nero's team stave off a Brainwashed Randall Kalish, the new Kamen Rider Bio-IXA. After Randall was defeated by Jessie and Phoenix, Jessie was inserted into the ranks of Nero's team. Jessie then went with the others and a knocked-out Randall when Nero faced off with Ray Blazer, Kamen Rider IXA. Jessie then went with the others to the Castle Challenge, where they would win a sword called the Sword of Eternal Night after they made it to a gold sarcophagus and opened it.
Phoenix was the winner of the Castle Challenge, but gave the sword to Jessie, which unlocked his new RX Arch-Angel form. Jessie then participated in the free-for-all battle royale and fought Rising IXA after the others were knocked out of the battle royale. Jessie thought he was going to win it, but Rising IXA used a feint to beat Jessie and take the immunity. After the second round was done, Nero chased after Davis Nash on the DenBird. After a quick duel, Nero drove back to find the city almost abandoned and his friends, including Jessie, entombed in dark pods that put them into a deep sleep.