Troy had been off sick for a while, and no-one had heard from him. He hadn't even updated his Facebook status, which still said, "Totally loving this whole singing thing."
Then he came back! Everyone danced around and sang, although presumably this didn't actually happen as the routine wasn't part of a singing practice/competition in the plot.
"Hey Troy," said Gabriella, who was most excited of all as she would get to totally french Troy after school. "You seem... different somehow. Have you had your eyebrows reshaped?"
"Nope," said Troy.
"Got some new threads, man?" asked Zeke.
"Nuh-uh," said Troy, shaking his head.
"We give up already. What is it?" said everyone.
Troy smiled. "Try... this totally awesome robot arm!" As he spoke he lifted up his right arm, which had been replaced with a huge metal monstrosity after he was involved in a terrible car crash.
"How did we miss that?" laughed everyone.