Musa and Tecna were in the dorm doing some research as Bloom, Stella, Flora, and Aisha have gone to Domino for the re. The Sirenix Book appears and tells that there is one test left to complete in order to obtain the Gem of Courage, which is hidden in the Yellow Reef, where they must "snatch courage from its jaws". Tecna isn't satisfied with the clue since it's so vague, so she consults her Guardian Spirit. The spirit tells Tecna and Musa that the Yellow Reef is on a planet that was saved by one person's courage. They find out that it's actually Domino, as it was Sky's courage that saved them from eternal ice. They have to act fast since there's two days left for them.
At Domino, Bloom takes Sky into the Domino Palace to meet her parents, to get reacquainted with them. She reminds him that it was his bravery that saved Domino from being stuck in an ice age, though he tells her he doesn't remember that guy who did so. She's still worried about Daphne, and Sky reassures her that she's probably fine.
Outside, Stella wasn't satisfied with the dresses she, Flora, and Aisha were wearing and finally puts a finishing touch on them before they enter the palace.
At Tritannus's lair, he continues to torture Daphne to make her talk, but she still remains defiant. Icy then casually brings up that a ceremony on Domino was happening today and that it would be a shame if something happened to her parents, making Daphne angry. Tritannus sends the Trix to Domino to capture Oritel and Marion while he goes to Domino's oceans.
Bloom has Sky meet Oritel and Marion, which seemed awkward for Sky since he can't remember meeting them let alone saving them. Stella, Flora, and Aisha enter to greet the royal couple, but then gets a call from Musa and Tecna, telling them the final gem was on Domino. Bloom goes to tell her parents of what she must do, and Oritel tells her to go on, as Sky will cover for her, making Sky nervous.
In Earth's oceans, Phylla, Illiris, and Desiryee escort Serena, the Gatekeeper of Domino's ocean gate, to protect her from Tritannus. As they swim, Desiryee notices something on the ocean floor. She picks it up, hoping Flora would know what it is. Unfortunately, Tritannus arrives and brushes off the other Selkies before absorbing Serena's powers. He breaks into the gate and Illiris and Desiryee follow while Phylla stays with Serena.
On the Odyssey Explorer, Bloom, Stella, Flora, and Aisha arrive above the Yellow Reef and transform to go under. They encounter Illiris and Desiryee, who tell them that Tritannus has passed through and Serena weakened. They take the Fairies to Serena, being escorted by Phylla, and Serena immediately bonds with Bloom, restoring her powers. Desiryee then gives Flora the pendant she found, which she recognized as the Pendant of Eraklyon then keeps to return to Sky later.
Back at the palace, Oritel and Marion began the ceremony of Domino's liberation as they present the Sword of Domino, and Sky. Suddenly, the Trix crash the ceremony and attack. Darcy takes out the guards by forcing them to fight each other. Sky, Oritel, and Marion immediately arm themselves to fight. Sky tells them that he still can't remember how to draw his sword before they all charge.
The Selkies lead the Winx (minus Tecna and Musa) to the Yellow Reef, where it gets tainted by Tritannus' pollution, causing the reef to mutate into spikey death traps. Bloom and the Selkies manage to escape its confines, but Stella, Flora, and Aisha were trapped within the spikes. Stella found to her horror that attacking the spikes would just only accelerate their growth. Aisha tells Bloom to do something before they wind up pin cushions. Bloom asks Serena to locate the source of the pollution, which was a crack in the ocean floor seeping out oil. Bloom quickly blasts it, sealing the hole and reverting the reef. They, then found the Gem of Courage, a green gem, floating nearby. Just as Bloom was about to retrieve it, it gets swallowed by a monster fish, which begins to attack them. They find to their shock that none of their spells were working on it, and Bloom decides to try one more thing, which was to literally "snatch courage from its jaws". Stella, Flora, and Aisha tries to stop her, but Bloom swims directly into the monster's mouth, apparently eaten. Suddenly, the fish glows and explodes into sparkles, leaving behind Bloom and her prize, the Gem of Courage. Their Sirenix Boxes get completed with five gems now adorning the points. At Alfea, Musa and Tecna finds their Sirenix Boxes also upgraded.
At the palace, Oritel and Marion were holding their own against the Trix, saying they are nothing compared to their ancestors. The Trix employ dirty tactics to capture Oritel and Marion in dark nets before finally turning them into ice statues. Sky gets angry and demands them to let them go, but gets shot down. Icy then calls up Tritannus, who was with Daphne. Sky managed to catch this, realizing Daphne was being held hostage. Tritannus forces her to watch in horror as her parents were iced over. When Icy cruelly pokes Marion's ice sculpture while mockingly wondering if she'd shatter if she fell over, Daphne finally broke down and agreed to tell Tritannus everything. Tritannus calls the Trix back. Before heading back, Icy decides to shatter Oritel and Marion anyway for cruel amusement. Just as she, Darcy, and Stormy launched a combined attack on the defenseless ice sculptures, Sky jumped in and destroys the attack after arming himself with the Sword of Domino. The Trix get angry for the interruption, but then get jumped by Bloom's group. Bloom was horrified at the state her parents were in and she immediately fights back. With the help from Sky and the other Winx, they curb-stomp the Trix yet again, who immediately retreat as they've done what they came to do. Sky wonders how they can revert Oritel and Marion back, and Bloom simply says together. Joining hands, power flows through the Sword of Domino, and Sky taps it on the royal couple, reverting them back to normal. Bloom was happy to see her parents alive and well again. Flora then presents Sky the lost Pendant of Eraklyon. Once Sky touched it, memories flooded back into him. Bloom was happy he regained his lost memories, and he finally presents the pendant to her. It seemed all was right, but then Sky remembered what he had witnessed earlier. He tells Bloom that Daphne had been taken hostage by Tritannus and that he had already forced her to tell him everything about the secret of Sirenix.
- Bloom obtains the Gem of Courage, officially ending their Sirenix quest.
- Desiryee finds the lost Pendant of Eraklyon in the ocean floor.
- Sky finally recovers from his amnesia.
- Sky finally presents the red heart-shaped pendant of Eraklyon to Bloom, which he had tried to do since the season started.
- Bloom bonds with Serena, thus restoring all of her abilities.
- Tritannus succeeds in making Daphne reveal the secret of Sirenix to him.
- Bloom finally knows that Daphne is in Tritannus' hands.
- King Oritel and Queen Marion
- Domino Royal Guards
- The events of the first Winx movie, Secret of the Lost Kingdom, is mentioned.
- This is the first time (revived) Domino is shown in the 2D part of the series.
- This is the first time we see Oritel and Marion in action in the animation that isn't a flashback.
- The Sword of Domino makes its first appearance since the first movie.
- This is the second time Bloom jumped into a monster's open mouth, the first being in "The Monster and the Willow" back in Season 1. Incidentally, both took place underwater.
- According to Tecna, there are over 100 locations called "Yellow Reef" in Magical Dimension. The only known one is in Domino.
- Interestingly, it seems that Domino's Ocean Gate is located at Earth.
- Starting with this episode, all episode title cards will appear in three-dimensional animation instead of two-dimensional animation.
- This is the second time Marion and Oritel were seen frozen. The first time is in The Secret of the Lost Kingdom.
- Lemmy didn't appear when Aisha went into Domino's ocean.
- Stormy's "S" decoration was backwards in Tritannus' lair.
- Molly Quinn as Bloom
- Amy Gross as Stella
- Alejandra Reynoso as Flora
- Morgan Decker as Tecna
- Romi Dames as Musa
- Keke Palmer as Aisha
- Matt Shively as Sky
- Larisa Oleynik as Icy and Marion
- Jennifer Cody as Darcy
- Kimberly Brooks as Stormy
- Josh Keaton as Oritel
- Adam Wylie as Tritannus
- Laura Bailey as Serena
- Amber Hood as Desiryee
- Lauren Weisman as Phylla
- Tara Strong as Illiris
"Sky, dear, there's a time for talk, and there's a time for action." - Marion