Stay Gold is the third and final EX story in Tokyo Mirage Sessions ♯FE, exclusive to the Encore version.
Arriving in the final section of the Area of Aspiration, Itsuki notices that Tsubasa is incredibly tired due to excessive training. She explains that her and Kiria have been tasked with performing a new song together for a commercial, and that she wanted to be on par with Kiria, hoping that one of the treasure boxes can help her. Kiria, however, notes that she is pushing herself too hard, as they are supposed to be equals, and Itsuki reminds Tsubasa of her previous endeavers.
Upon reaching the final area and dealing with a surprise Mirage attack, Tsubasa finally realizes that she is capable of working with Kiria as is, causing the final treasure box to disappear. The two perform their new song, She Is..., to massive acclaim. Later, at the Bloom Palace, Itsuki and Tsubasa ask Tiki why the final treasure box disappeared, and she theorises that it was because Tsubasa was able to find the solution on her own, whereas the area was meant to help those who couldn't. Afterwards, Tsubasa thanks Itsuki for all of his help.