Where are we going?

After 10 mins., Almira spoke up.
"Where are we going anyway?"
The car drove past a sign that said, "Nowhere... 200 kms."
Jem replied, "Umm... Nowhere?"
Jasper said, "We'd better start in Mrs. Grecia's house first."
So Jem turned the vehicle around to where they came from a day before.

A bare lamppost. Nothing. No trail of blood. No amputated body parts. No clues. Or were there?
Yanna noticed, "I don't notice anything particular about this lamppost? Why was Joshua here in the first place?"
Nicah replied, "Sets me thinking. Why?"
Joshua said, "I knew camera eyes were going to be useful someday."
Almira said, "Guys! I found a cellphone?"
"Where?" Jem asked.
"Behind the bushes over there?"
"How dare that person leave his or her cellphone lying around like that! He or she doesn't know how to care for it!" Then Jem got her cellphone and talked to it, "I won't lose you. Oh... no I won't!"
"Anyway..." Joshua said.
Nicah looked. "It's Mishka's!"
Yanna asked her, "How do you know?"
"See? Look at my text! I texted him a while ago to see if he was okay. Maybe that's why he didn't reply. It was here all along."
Yanna got the phone. "Huh?" She clicked the New Message button. As always, all messages a person writes are not deleted until sent. A message popped out. A message for them.

"Jet...lag..."

Almira asked, "What does that mean?"
Joshua replied, "It means go to Jet's house. Jet, our friend, and lag, which in another language means house."
Jem asked, "And what language is that?"
"Umm... I forgot."
Nicah said, "Well... it's worth a try..."
They climbed back in the car.
A minute of silence.
"Where's Jet's house???!"