The Prince's Goodbye Lullaby

is the twenty-fourth episode of Kamen Rider Den-O. It features the debut of Den-O Wing Form.
==Synopsis==
After Ryotaro becomes arrested while trying to return Sieg's host, Hana tries to teach the troublesome Imagin what it means to be a real, responsible prince.
==Plot==
After being arrested by the police, Ryotaro is questioned on his involvement with the kidnapping of baby Yūsuke Takayama. During the interrogation, Momotaros, Urataros, and Kintaros attempt to help him, as he has no knowledge of the event. On the DenLiner, Hana and Yuto try to understand what is going on, and Hana tries to talk some sense into Sieg about what he has done to Ryotaro. Hana tells him that a master has to take care of his servants, and with a slap, Sieg develops new respect for Hana and begins calling her Princess. Sieg manages to speak through Yūsuke to convince Shiori Takayama to acquit Ryotaro. Ryotaro is then brought to the Takayama mansion to be thanked, with Sieg possessing him with intent to live the good life forever. However, because he opened a contract with someone with very little memory like baby Yūsuke, Sieg begins to dissolve away. He goes to say goodbye to Yūsuke, but he is interrupted by the Scorpion Imagin's second attempt to bring Shiori to his contractor. Before Yuto can intervene, S-Ryotaro transforms into Kamen Rider Den-O Wing Form, managing to knock the Scorpion Imagin down. However, Sieg's dwindling strength allows the Scorpion to escape with Shiori. Sieg asks Ryotaro to save his mother, as he follows the Scorpion Imagin back in time to February 22, 2002, the day that Akio Masuda was fired by the Takayama family. Den-O fights the Scorpion Imagin as Rod Form and then Ax Form, and defeats him with a Dynamic Chop. Back on the DenLiner, Sieg continues to waste away until Ryotaro returns and shows the Owner a Rider Ticket bearing Sieg's image and the date June 1, 1997, that he got after using a Rider Ticket on Shiori. In reality, Sieg had already fulfilled a contract with the mother, before forging his contract with Yūsuke. Thanks to this, the DenLiner arrives on the day of Shiori's wedding, and Sieg leaves the DenLiner to live happily in the past.
==Cast==
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
===Guest Cast===
*: 
*: 
*: 
*Police: , 
*Police Officer: , 
*Driver: 
*Reporter: 
*Servant: 
*: 
===Suit actors===
*Kamen Rider Den-O/Momotaros: 
*Urataros: 
*Kintaros: 
*Ryutaros: 
*Deneb: 
*Scorpion Imagin: 
*Kamen Rider Den-O Wing /Sieg: 
==Forms==
*Den-O: Wing Form, Plat Form, Rod Form, Axe Form
==Notes==
*As part of Super Hero Time, this episode aired alongside episode 20, .
*Viewership: 6.1%
==DVD releases==
Kamen Rider Den-O Volume 6 features episodes 21-24: Fighting Style, An Unspeakable Future, Enter the Prince, Kneel Down to Him! and The Prince's Goodbye Lullaby.
Blu-ray Box 2 comes with 18 episodes.
Category:Kamen Rider Den-O
Category:Episodes
Category:New Form Episode