The Alfea Underfloors are a network of different rooms with various contents. One unnamed room contains magical objects including stones, vases, tiaras, armor, and statues of the Alfea Champions.
In "Legendary Duel," Daphne suggests the Winx search the Alfea Underfloors for a magical object they can trade Rumpelstiltskin for the Legendarium Key. Later, Daphne reveals the artifact chamber's hidden door at the end of a hallway. Upon entering, she reveals to the Winx and the pixies the statues of the Alfea Champions. Bloom then prompts everyone to search for an object. The Winx and pixies find various items, including tiaras with miniaturizing and growing properties, vases, and a Speed Stone. Later, the statues of the Alfea Champions can be seen coming to life as Selina invokes them with the Legendarium.
In The Secrets of Alfea, the Alfea Underfloors are first seen when Bloom finds a book titled The History of Alfea in the library. She later uses the map of the castle inside to visit the underfloor's Costume Depository to find a dress she can wear to the Traditional Meeting Dance between the Alfea Fairies and Red Fountain Specialists but, on her way down, she catches some of the Specialists storing their enchanted gifts for the fairies until it is time to present them. This prompts Bloom to hurry and find a dress.
After managing to find a magic dress and stumbling upon the Trix cursing the Specialists' enchanted gifts, she accidentally takes refuge in the Magical Labyrinth, and has to use the dress' thread to find her way out as the Trix pursue her. After making her escape, Bloom alerts the Winx of the Trix's curse and joins in their counterspell to revert it. The Trix, however, get stuck in the labyrinth and end up as victims of their displaced curse.
In The Stone of Memories, Faragonda calls all the Alfea fairies into the Hall of Memories to reveal to them a new power to commemorate the 100th Year Anniversary of Alfea's founding. She calls Bloom out of the crowd of students to bestow this new power to her believing her to be worthy enough to handle it. Handing her a stone, Faragonda explains that it is the Stone of Memories and its wielder can use it to relive past memories if they so choose. She then asks Bloom if she is ready to accept such a power but before Bloom can accept, a trio of Crowrats fly into the hall and attack.
The Crowrats dodge each one of Faragonda's attacks and end up snatching the Stone from Bloom, causing a great flash of light to fill the Hall. Once it dissipates, everyone finds that Bloom and the Crowrats have disappeared. To make matters worse, Faragonda felt the Trix's presence emanating from the Crowrats and fears what the infamous trio of witches plan to do with the Stone. She then reveals to the Winx and the rest of her students that Bloom has now been trapped within her memories and they can do nothing but wait and hope she can make it out safely.
Since this issue is written like a Choose Your Adventure! book, Bloom can brave through that labyrinth that makes up her disorganized memories and blow back the Trix to retrieve the Stone of Memories should the reader make all the right choices.
Back in the Hall of Memories, Bloom is greeted by Faragonda and hugged by the Winx as they rejoice over her safe return. After being asked of what happened, Bloom reveals that the Trix had magically inserted themselves into her memories to try and change them but, seeing as how she made it out, she was able to defeat them yet again. Faragonda congratulates Bloom on mastering the newfound power of the Stone of Memories and assures her that she will try to find a more suitable prison for the Trix; namely, one far from Magix. Stella then asks if Bloom enjoyed traveling back in time through her memories to which Bloom admits to finding it to be a wonderful experience despite the circumstances, however, she finds being able to change her life through the choices she makes everyday to be a much better experience.
In Magic Travelix, Faragonda leads the Winx to the Hall of Memories and says that here they can find an obscure, special magical power called Travelix. She then entrusts them with the Stone of Memories imbued with the power of Travelix so that they may travel back in time to the exact moment that was erased from the memories of Alfea by their enemy.
After instructing them to stand around the Stone and focus their powers, the Winx transform into Travelix fairies before traveling into a time portal.
Once they emerge from the other side, the Winx find themselves in the Hall of Memories again, but this time a few hours in the past, as confirmed by Musa when looking at the clock on the wall. Tecna then urges the Winx to be careful as they still do not know who they are dealing with.