<Tr> <Td_colspan="7"> Sirena's sister, Aquata, returns to Mako Island with good and bad news . She reveals that Sirena is now allowed to return to the pod, but Lyla and Nixie are still banished . Though Sirena is reluctant to leave her two friends, they both insist that she go . Meanwhile, Zac discovers the underwater entrance to the moon pool and confronts Lyla and Nixie, demanding they tell him about the trident's connection to the moon pool . When they refuse, he threatens to take over the moon pool . The next morning, Sirena leaves with Aquata while Nixie and Lyla confront Zac at his home . Another battle ensues with the two girls finding themselves overpowered once again . However, Sirena returns just in time to knock the trident from Zac's grasp . Lyla, seizing her chance, swims off with the trident and hides it in a small opening in the rocks . Afterwards, Sirena decides to stay with Lyla and Nixie rather than return to the pod . </Td> </Tr> <Tr> <Th> 22 </Th> <Td> 22 </Td> <Td> "Evie Times Two" </Td> <Td> Grant Brown </Td> <Td> Max Dann </Td> <Td> 15 December 2013 (2013 - 12 - 15) </Td> <Td> 15 September 2013 </Td> </Tr> <Tr> <Td_colspan="7"> When David delivers a seafood order to Rita's house, Evie, who is still suspicious of the girls, tags along hoping to find out more about them . Meanwhile, Rita's cat, Poseidon, becomes magically enchanted after stepping through a puddle of spilled potion . After encountering Evie, who was snooping around the house, Poseidon transforms into an exact duplicate of Evie but retains the mind and instinct of a cat . David mistakes feline Evie for the real Evie and takes her back to the cafe . Later, feline Evie goes to the beach with Carly where Cam notices her odd behaviour and calls Zac for help . While searching for Poseidon, the girls run into Zac and "Evie" at the beach and eventually realise what has happened . Lyla helps Zac keep the real Evie and Poseidon apart while Nixie and Sirena work on a way to restore Poseidon to cat form . </Td> </Tr> <Tr> <Th> 23 </Th> <Td> 23 </Td> <Td> "Zac's Choice" </Td> <Td> Grant Brown </Td> <Td> Chris Roache </Td> <Td> 22 December 2013 (2013 - 12 - 22) </Td> <Td> 15 September 2013 </Td> </Tr>

When does mimi find out zac is her brother