- M stands for Money and Memories.
- The first part is "How to Get to Heaven."
- The second part is "Play With a Joker."
Spoilers abound. This is a recap page; if you don't want lots of very specific information, you're better off on the main series page.
At the Narumi Detective Agency, Shotaro gets into another argument with Akiko over her cramping his style until Philip changes the station to the Healing Princess radio show hosted by Wakana Sonozaki as she mentions the rumored Million Colosseo casino during her Futo's Mystery Tour segment. By then, a couple who owns a pastry shop arrive to hire Shotaro to follow their daughter Yuko Izumi, who has been acting strange recently. Losing Yuko because of Akiko, Shotaro goes to Watcherman for answers, leading them to Goro Murasame who came from the Million Colosseo and lost everything. Leaving him to contact Philip, who freezes up upon the mention of the word "family," Murasame is attacked by the casino owner Taizo Kaga, the Money Dopant. Shotaro pursues the Dopant, but is forced to fight the monster on his own until Philip comes to and they form Kamen Rider Double. Transforming into HeatJoker and about to finish is opponent off, Double is hit from behind by a mysterious Dopant, covering the Money Dopant's escape. After getting an autograph of Wakana for Philip while searching for clue in the roads leading to it, Shotaro learns of a fake public bus that Yuko takes to the Million Colosseo, following close behind on his own. When he discovers Akiko in the bus, he is attacked once more by the Money Dopant, transforming into Kamen Rider Double and then assuming the form of CycloneMetal to fight the Dopant. However, the Dopant reveals his ace in his Life Coins as he unknowingly causes Philip to freeze up, leaving Shotaro to fend for himself as Akiko enters the Million Colosseo.
After surviving the Money Dopant's attack, Shotaro gets a glimpse of Philip's family as the young man comes to and becomes crazed as he searches the Gaia Library for "My Family" only to find a book with the pages torn out. Shotaro attempts to put the worried Philip at ease until he gets a call from Akiko from the Million Colosseo. She uses the Bat Shot to broadcast Yuko's loss at the roulette wheel after she bet her life to win back her earnings, with the Money Dopant sealing the woman's soul into a Life Coin. When Akiko reveals herself to and nearly gets herself killed, Philip challenges the Money Dopant to a game of chance to save her and get the Life Coins, using his and Shotaro's Gaia Memories as collateral. While Philip researches on everything gambling related, Shotaro ruminates on the family he saw in Philip's memory before he and Philip board the bus to the Million Colosseo. Philip easily predicts the results of the roulette, winning most of the Life Coins until Kaga mentions the word "family", breaking Philip's winning streak and winning back his Life Coins along with most of the Gaia Memories. Tagging in for Philip, Shotaro then challenges Kaga to a winner takes all game of Old Maid. Though Kaga played Shotaro into a position where he can win, Shotaro turns the tables by using the Double Driver to link his mind with Philip's to win with his partner's abilities. Enraged, Kaga transforms into the Money Dopant and escapes as Double chases him down, assuming LunaJoker and LunaMetal to fight him. When the Money Dopant attempts to use the word "family" to make freeze Philip up again, he resolves that Shotaro and Akiko are family enough for him at the moment. Double transforms into HeatMetal and causes the Money Memory's Memory Break, freeing Yuko Izumi and everyone else from the Life Coins. On the radio later, Wakana Sonozaki mentions the newest mystery to hit Futo: Kamen Rider Double.
Elsewhere, after being tested by Wakana as the ClayDoll Dopant to see if he is worthy of the Nasca Memory's power, Kirihiko's wedding to Saeko goes off without a hitch, and the new family pose for a photo together, all transformed into their Dopant forms.
- Bittersweet Ending: Kaga's casino is shut down and everyone who sold their own lives are free again, but those same survivors are also stuck in crippling debt.
- Elaborate Underground Base: The casino itself.
- Heroic BSoD: the first time Phillip gets this upon mention of his family.
- Spooky Photographs: The Sonozaki family photo.
- Very Special Episode: thanks to the whole gambling Aesop.