Mako: Island of Secrets S01 E04 Lyla Alone

"The mermaids are back and this time they're real."

Nixie and Sirena won't help Lyla try to "zap" Zac's powers, so Lyla decides to do it alone. This misfires when a waitress spills a drink on Lyla and Lyla rushes to hide in the refrigeration room before she transforms into a mermaid! When she can't dry her tail, Nixie and Sirena must save her before she is discovered!