The Trix and Tritannus torture Daphne to find out how to get Sirenix, then crash the Red Fountain Wind Rider competition. Meanwhile, the Winx go to Linphea to find the Flower of the Depths and a clue to the Gem of Courage's location.
While Daphne is questioned by Tritannus about Sirenix, Alfea is under attack from a Trix dark lion spell and the Winx search for the Gem of Courage.
The episode starts with the Trix torturing the captured Daphne as Tritannus interrogates her about the secret of Sirenix. She refuses to say anything despite the pain she is experiencing. Icy then suggests they go after Bloom in order to force Daphne to talk.
At Alfea, a wind-riding event with the Specialists takes place. Brandon, Riven, and another Specialist take the first course, and Bloom worries about Sky, who is still trying to regain more of his lost memory. Bloom goes over to encourage him that he can do this.
Unknown to everyone else, the Trix arrive via stealth invisibility to locate Bloom. Stormy goes down to mess around with Flora a bit. The witches were surprised to see that Kiko was able to sense them, so Darcy makes invisible shadow clones of himself to chase after him.
In the dorm room, Bloom finds the Sirenix Book which suddenly appears to tell her the next clue. According to it, they must find the Flower of the Depths. She goes down to tell the others. Flora theorized it must be on her home planet, Linphea, in the Ocean of Flowers.
Tritannus swims towards the Linphea Gate to invade its waters. He ambushes Desiryee, the Gate Keeper, and absorbs her power before porting to Linphea's oceans. Desiryee quickly follows him through before passing out. Tritannus finds the Flower of the Depths and prepares a little surprise on it.
Sky, Helia, and Timmy are to race next. Sky had a bad start but quickly recovered, gradually remembering how to use a wind rider. That was when the Trix made their move and caused the wind riders to change into mutant lions, causing a panic in the courtyard. Bloom, Tecna, and Aisha stay behind to fight them while Stella, Flora, and Musa go to Linphea.
At Linphea, Stella, Flora, and Musa arrive at the Ocean of Flowers. Flora warns the girls that the flowers underwater can be quite carnivorous and tells them to watch their backs. They transform and go underwater where they meet up with Illiris and Sonna. They guide the girls to see a weakened Desiryee. Flora goes over to her and they bond, restoring her powers. Desiryee then leads them to the Flower of the Depth.
At Alfea, Bloom, Tecna, and Aisha continue to fight the monster lions. Sky notices that the lions seemed to target only Bloom. She then tries to lead them away after knowing this, but Sky had a different plan in mind. He has her position herself in one of the wind rider course obstacles; flaming cages. Ready, Bloom taunts the lions to come get her. After taking the bait, Sky pulls Bloom away once the mutant lions get trapped in the flame cages and revert back to wind riders again, ending the threat.
In the ocean of Linphea, Stella's group finds the Flower of the Depths, where Flora enters it, finding a small white flower in its center. Unfortunately, Tritannus had cursed it with his pollution, causing it to mutate and attack the girls. Stella and Musa try to fight it, but Flora asks them to stop. She attempts to use her powers to heal the Flower back to its original state, and succeeds. It appeared to be talking to them, so Flora calls upon her Guardian of Sirenix to help translate. She tells them that there is one more test they must complete to find the Gem of Courage, and that the Sirenix Book will give them the final clue.
At Alfea, Sky decides to take Bloom for a ride on his wind rider. Bloom suggests the Gorge of Roccaluce, hoping that would also awaken more memories in him. Tecna and Aisha think it is too risky as they still have no idea what caused the incident earlier.
At the Gorge, Sky and Bloom were enjoying the scenery, until Stormy appeared and shot them down. Sky gets angry at the sight of the Trix, who intend to capture Bloom.
Tecna and Aisha get worried as Bloom was not answering their calls. Aisha then gets a call from Stella to report their success. She is happy for them, but then tells her to meet her and Tecna at Roccaluce Gorge as she has a feeling Bloom is in danger.
Bloom was too hurt to try and transform to fight the Trix. Sky tries to fight them off, but was incapacitated by Icy. Icy, Darcy, and Stormy are about to finish him off, but Bloom quickly jumps in to take the blow. The Trix were about to capture her when the Harmonix powered Winx fly in and curb-stomp them. The Trix angrily retreat, promising that they will capture Bloom. Sky was thankful Bloom was all right, and that it was a brave thing she had done. She replied that it is what he did for her back then. Bloom, however, is still scared that the times they have had together may just vanish, but she wants them to form a future without regrets.
- Flora bonds with Desiryee.
- Sky regains more of his memories.
- Flora heals the sea plant in the deepest part of Linphea's ocean - the Flower of the Depths, since Tritannus poisoned it.
- Only three days remain until the lunar cycle ends.
- Flora's Guardian of Sirenix
- Flower of the Depths
- Wild Lion Monster
- Ocean of Flowers
- Roccaluce Gorge
- Winx Club
- Alfea Staff
- Alfea Students
- Red Fountain Staff
- Guardians of Sirenix
- "Darkened waves of twilight reign, tame her mind and bring her pain" - Used by the Trix to torture Daphne so that she may reveal them on how to gain Sirenix.
- Mirror Attack - Used by Darcy against Kiko.
- Storm of Numbers - Used twice by Tecna, first against the lions, then later against Stormy.
- Dazzling Spiral - Used by Stella against Stormy.
- Shining Mirror - Used by Stella to defend herself.
- Reverberating Notes - Used by Musa against mutated Flower of the Depths.
- Diapason - Used by Musa against Darcy.
- Mystic Wrap - Used by Aisha against Icy.
- Dancing Whirl - Used by Flora against Icy.
- Fire Blade - Used by Bloom against the monster lion.
- Fall Vortex - Used by Flora against the source of mutated power on the Flower of the Depths.
- Ice Attack - Used by Icy against Flora and Aisha, but failed.
- Stella's lack of driving skill returns when trying to drive the Odyssey Explorer. The first time she drove in The White Circle, she drove so badly Aisha had to drive instead.
- This is the second time Linphea has been shown, the first being the twelfth episode of Season 3.
- In the Nickelodeon dub, this is actually the tenth episode of Season 5, but this is because the episode "A Magix Christmas" did not air until December 9.
- In the Italian version, the Winx have longer than a month to complete their missions. This is why Bloom goes home for Christmas, and everyone else take time to watch the Competition.
- This episode aired before the tenth episode.
- Sky's gem on his chest was pink, but in the later scene, it was blue.
- When Flora bonded with Desiryee, her ponytail moved along her head and past her ears.
“Darkened waves of twilight reign tame her mind and bring her pain!”
“Very pretty! Hello there, keeper. Desiryee, keeper of the Linphea gate. Only one more keeper, and I can enter the Infinite Ocean!”
“The Flower of the Depths says, you were very brave Flora, and deserve to find the Gem of Courage.”
“What!? Oh, come on!”
“Stella! Didn't you say could drive this thing?!”
“I said that I wanted to drive it, not that I knew how!”