"I'm sorry," Carly said to her phone. "But I don't know where Evie is... The last time I saw her was yesterday morning... Yes, I'll ask Zac... Okay, thank you, bye."

Carly hung up and stared at her phone for a few moments, before slipping it into her back pocket and wiping the counter of the Ocean Café. Cameron, who was looking at his phone, walked towards her.

"What's up?" He asked.

Carly shrugged, looking uneasy. "Evie's Dad just phoned me, Evie never went home last night."

Cameron narrowed his eyebrows with confusion. "Are you serious?"

Carly nodded. "Where could she have gone?"

Cameron thought for a moment. "You don't think Erik..."

"Why would will kidnap Evie?" Carly asked.

Cameron shrugged. "Why wouldn't he? He'll do anything to make Zac lose, with the full moon approaching."

"What use would a land-girl be to Erik? He had no use for Mabel."

"But Mabel's a mermaid," Cameron reminded Carly.

"But Erik didn't know that," Carly reminded her boyfriend.

David and Sirena entered the café through the storage cupboard, after they had taken the box of knives and forks and spoons into the cupboard to keep them safe until morning.

"What's going on?" David asked.

"Evie is missing," Carly said.

"What do you mean?" Sirena questioned Carly.

"I mean, she didn't go home last night," Carly said. "Evie's Dad phoned me up a few moments ago."

"But, Evie wouldn't just leave - " Sirena began.

" - Unless Erik had something to do with it, " David finished.

As if on cue, Zac entered the café. He had a slight spring in his step, and he smiled.

"Great news! Nixie and Weilan replied, and they've told us their location! I'm heading over to Rita's now, and me, Ondina, Mimmi and Lyla are heading out there."

"Why didn't you invite me?" Sirena asked, looking and sounding hurt.

Zac didn't answer this. Instead, he looked around the café. "Wait, where's Evie?" He asked.

"She's gone missing," Cameron sighed. "She didn't go home last night."

Zac looked at his best friend, looking confused, and deep in thought. Eventually his eyes widened with horror, and he whipped his phone out of his pocket, typed in a phone number, and held it to his ear.

"Hello? Yes... It's me... Evie's fine, she didn't feel well last night, so she spent the night at my house... Yeah... She slept in the spare room... She's okay... I'll let you know... There's nothing to worry about... Yes, thanks... Talk to you soon."

Zac hung up, and exhaled deeply.

"What was all that?" David asked, nodding to Zac's phone.

"I called Evie's Dad," Zac replied, putting his phone away. "I remember Mabel said something about Erik's plan: Erik had something to do, which would make me surrender so he could activate the Chamber... She didn't know what it was, but now I realise that it's taking Evie! We have to act fast, I need to talk to Erik."

Cameron looked out of the window. "That's funny," he said absentmindedly. "I spoke to Erik the other day."

Everyone stopped what they were doing, and slowly turned their heads in unison to look at Cameron. Cameron turned to face everybody.

"What?" He asked.

Zac raised his hands and clenched his fists. "You did what?" He asked angrily.

Cameron nodded. "I did," he said. "It was about two days ago."

"Why didn't you tell us?!" Zac carried out in frustration.

Cameron shrugged. "I completely forgot, sorry."

"What did he say?" Carly asked.

Cameron thought back to that last afternoon. "He said... He said that if I work for him, he would allow me to go to the Moon Pool and become a merman."

"What?!?!" Zac cried. "Cam, why didn't you tell us this before?!"

"I forgot," Cameron repeated casually.

"Hold on," Sirena said. "If Cameron goes to pretend to work for Erik, he could find some information regarding their new plan and report back to us."

Carly nodded. "Good idea, Sirena. And, Cameron could also free Nixie and Weilan and Evie whilst finding out all about Erik's plans."

"Hold on, what?" Cameron asked, blinking at his friend.

"Well, you have frequently complained that you never get to help the mermaids," David reminded Cameron.

"Yeah, but - " Cameron began.

Zac tried to force a smile as he calmed his nerves. "Okay, Cameron goes to work for Erik, to tell us information. You should probably go now."

*****

Cameron had reluctantly gone to find Erik, and Zac and Sirena headed to Rita's, to tell them what Cameron was doing, and about Evie's disappearance.

But when they got to Rita's house, she wasn't there. Lyla, Ondina and Mimmi were in the grotto. Mabel was there too.

"Where's Rita?" Sirena asked them, as she sat down and picked up Poseidon, Rita's cat, and placed him on her knee.

Ondina shuffled away from Sirena. Ondina had never liked Poseidon. "She went out again," Ondina sighed. "I think she went to meet Veridia. But we weren't allowed to go. We had to wait for you guys."

Zac sat down besides Lyla. "Evie's gone missing," he said slowly.

"What?!" Everyone cried.

"And Erik took her?" Mimmi asked.

Zac nodded. "I think so."

"Why would Erik want Evie?" Mabel asked. "Unless - "

Zac nodded. "I bet he's going to threaten to hurt her unless we let him activate the Chamber."

Just then there was a splash coming from Rita's pool. Everyone looked at the doorway, ready to tell her about Evie, but then they heard another splash... And then another... Ams another... And one more...

"Four," Mabel whispered.

"Erik, Josh, Gareth and Matteo," Zac whispered.

Everyone stood up and readied their moon rings, except Mabel and Zac, and they waited for Erik to appear...

Except it wasn't Erik... It was Rikki.

Rikki looked around blankly, then looked at her mermaid friends and smiled.

"Guess who came to save the day?!" Rikki exclaimed happily, almost singing.

"Rikki!" Mimmi laughed. "What are you doing here?"

Rikki entered the grotto, followed by Cleo, Emma and Bella. Hugs and handshakes were exchanged (and Mabel was introduced) and everyone sat down to converse.

"Isn't it obvious?" Bella asked. "We're here to help you!"

"Yeah, with your 'little' Erik problem," Rikki added.

"You know that Erik's back?" Ondina asked.

Cleo nodded. "Yes. Rita has been training us with our moon rings for the past six months!"

"We were hoping to surprise you," Emma said. "Unfortunately, Rita came and told us about Erik. So we quickened up the lessons, and now here we are!"

"Wait," Mimmi said. "So, every time Rita left unexplained, she was really going to see you?!"

Rikki nodded. "Yeah, it was all part of the surprise."

"Where's Rita now?" Mabel asked timidly.

"We ran - well, swam - into Veridia on the way here. They went off to talk," Rikki replied.

"So how has your training been?" Sirena asked.

"It's been awesome," Bella smiled. "We've improved our magic greatly, and we have learnt lots of new spells and tricks."

"Good," Zac said. "Because we'll need them."

"Tell us what's been happening," Emma said.

Zac, with the help of the mermaids, enlightened Cleo, Emma, Rikki and Bella about everything that had happened, including: the three new merman; Nixie, Weilan and Evie being kidnapped; Erik's plan in full detail and Cameron's conversation with Erik.

"And Nixie, Weilan and Evie are still on Dr Denman's boat?" Cleo asked, hatred in her voice.

Lyla nodded. "First it was Nixie, then Weilan, and finally Evie yesterday."

"So what's our first plan?" Emma asked.

"I found a way to contact Nixie and the others," Mimmi said. "They aren't hurt, which is great to hear. Anyway, we are going to let Cameron work for Erik, and he will report information to us, and try save Nixie, Weilan and Evie. Then, on the full moon, we will all be waiting outside the Merman Chamber for Erik and the others."

"How long have they been gone?" Emma asked.

"Nixie has been gone for about two months," Sirena said.

Rikki paused. "... It's been two months and you haven't been able to save them? That's pretty poor work..."

"RIKKI!!" Cleo hissed angrily.

Rikki held up her hands. "I'm sorry! Look, contact Nixie and the others, and Cameron will set them free. Then during the full moon we will go to the Merman Chamber and stop them in their tracks... Let's go!!"