|“||I follow her gaze to the roof, where there’s now a jagged hole the size of a bus. As I’m staring, a tall man in a trench coat with long red hair walks to the edge of the hole. He points at me.||”|
-Marina, The Power of Six
The Battle of Santa Teresa is a major conflict between the Loric and the Mogadorians in a small town in Spain and reaches its climax near a lake. It marks Marina's first major confrontation with the Mogadorians since living in the orphange for a number of years; the introduction of the apparent Number Ten, also known as Ella, and her Cêpan Crayton; and the arrival of Number Six, who leaves Four and Sam to track Marina.
The Mogadorians know of Marina's location for a while, though Crayton has been working behind the scenes to create distractions to lead them off her scent while he works to find her chest and leave Spain with her. However, after reuniting with her Chest and seemingly setting off a tracking device (Red Crystal), she is careless and uses her Telekinesis to levitate Adelina, her Chest and herself from the belfry which, unbeknownst to her, is witnessed and attracts a large amount of media coverage. The next morning a girl, Miranda Marquez, with looks similar to Marina's is found dead at the school. Marina believes that the Mogadorians could have confused Miranda for her.
Marina finally manages to convince Adelina that the Mogadorians have found her after she sees Crayton, who she thinks is a Mogadorian, speaking to Héctor. The Mogadorians' arrival becomes inevitable, so Crayton panics and lights a giant Loric symbol to alert the other Garde, hoping they would come and help fight.
|“||I'm going to mow every damn one of them down!||”|
–Crayton, The Power of Six
Adelina and Marina go to the nave to retrieve her Chest, but are followed by Mogadorians. Adelina tells Marina to run and to be brave before facing the Mogadorians head on; she demonstrates some impressive fighting skills before she is ultimately killed by a sword through her heart.
Marina is attacked by another Mog who is able to inflict damage using his blaster; Marina realises that the Loric Charm must now be broken and that they are able to kill her. She is saved by Crayton, the man she had seen talking to Héctor and suspected to be a Mogadorian. He reveals that he and Ella are Loric and that Ella is in fact an Aeternus, meaning she can switch between ages that she has lived.
They fight their way through the convent to meet Héctor in a getaway truck. He drives them towards the lake and are followed by a convoy of Mogadorian trucks fitted with guns. At the lake, Crayon summons Olivia, one of Raylan's Chimærae, who emerges from the lake in the form of a giant lizard and defends them against the oncoming Mogadorian attack. Olivia is eventually overwhelmed by a swarm of Krauls and is killed.
Marina and Ella flee into the woods, but are chased by a Piken. Marina locks Ella and her Chest inside a hollowed out tree and distracts the Piken from finding her. Marina is almost knocked off a cliff but manages to kill the beast before she is shot by a Mogadorian cannon. A storm begins to brew and a lightning bolt shoots from the sky and kills the soldier. Marina and Ella return to the lake to find Héctor injured and a wave of Mogadorians and Krauls gaining on them.
The storm gets worse and soon Number Six arrives. Marina is mesmerized by her strength as she battles the Mogadorians using her Legacies and the Mogadorians weapons against them. Four Pikens are released and they charge down the mountain towards them. Two are killed before they reach the group, Six battles the third and the fourth snatches Héctor's body in its fist and throws him into the lake; he is killed instantly. Six finishes the last Piken by severing its head from its body using a lightning strike.
Crayton believes that the Mogadorians know the Garde are getting stronger and will start to throw everything they have at killing them. He believes that Setrákus Ra, the leader of the Mogadorians, will likely arrive on Earth if he hasn't already. Crayton convinces Marina and Six to go with him to India to follow a lead on another member of the Garde.
|“||If Setrákus Ra thinks it's going to be easy, he's got another thing coming.||”|
–Crayton, The Power of Six