Bumblebee had brought Sam and Mikaela into the alleyway, to meet the other Autobots who had just arrived on Earth. He lets them out just as the other Autobots begin arriving at the Alleyway. And you're just invisible until they call you out. The Autobots know that you're there, but Sam and Mikaela don't, due to you being invisible

Optimus Prime: transforms first and kneels to be at eye level with Sam Are you Samuel James Witwicky, descendent of Archibald Witwicky?

Mikaela: They know your name. she says in awe

Sam: Yeah?

Optimus Prime: My name is Optimus Prime. We are autonomous robotic organisms from the planet Cybertron.

Ratchet: But you can call us Autobots for short.

Sam: Autobots.

Jazz: What's crackin', little bitches? does a flip

Optimus Prime: My first lieutenant.

Jazz: Hyah!

Optimus Prime: Designation Jazz.

Jazz: This looks like a cool place to kick it. does another flip and lands carelessly on the hood of an old abandoned car

Sam: What is that? How did he learn to talk like that?

Optimus Prime: We've learned Earth's languages through the World Wide Web. My weapons specialist, Ironhide.

Ironhide: takes out his cannons, trying to be intimidating You feeling lucky, punk?

Optimus Prime: Easy, Ironhide.

Ironhide: Just kidding. I just wanted to show him my cannons.

Sam: exhales Heh.

Optimus Prime: Our medical officer, Ratchet.

Ratchet: Mmm. The boy's pheromone level suggests he wants to mate with the female.

Mikaela: Ermm...

Sam: whistle

Optimus Prime: You already know your guardian, Bumblebee. he says as Bumblebee starts shadow boxing

Sam: Bumblebee, right?

Bumblebee: Check out the rep, yep, second to none-

Sam: So you're my guardian, huh?

Bumblebee: electronic squeal

Ratchet: scans Bumblebee His vocal processors were damaged in battle.

Bumblebee: coughs

Ratchet: I'm still working on them.

Mikaela: Why are you here?

Optimus Prime: We are here looking for the AllSpark. And we must find it before Megatron.

Sam: Megawhat?

Optimus Prime: Our planet was once a powerful empire. Peaceful and just. Until we were betrayed by Megatron, leader of the Decepticons. All who defied them were destroyed. Our war finally consumed the planet, and the All Spark was lost to the stars.

Hologram Megatron: growl

Optimus Prime: Megatron followed it to Earth, where Captain Witwicky found him.

Hologram Megatron: growl

Sam: Oh– My grandfather.

Optimus Prime: It was an accident that intertwined our fates.

Hologram Sailor 1: Come back!

Hologram Sailor 2: I think the dogs have found something.

Hologram Archibald: The ice is cracking!

Hologram Sailor 3: Captain!

Hologram Sailor 4: Captain! Grab my rope, Captain!

Hologram Sailor 5: Captain!

Hologram Archibald: I'm all right, lads!

Hologram Sailor 6: Can we throw you a rope, captain?

Optimus Prime: Megatron crash-landed before he could retrieve the Cube.

Hologram Archibald: Men! We've made a discovery!

Hologram Sailors: indistinct yelling

Optimus Prime: He accidentally activated his navigation system.

Hologram Megatron: speaks in Cybertronian

Hologram Archibald: Aaaaaah!

Optimus Prime: The coordinates to the Cube's location on Earth were imprinted on his glasses.

Sam: How'd you know about his glasses?

Optimus Prime: eBay.

Sam: eBay.

Ratchet: If the Decepticons find the All Spark, they will use its power to transform Earth's machines and build a new army.

Optimus Prime: And the human race will be extinguished. Sam Witwicky, you hold the key to Earth's survival.

Mikaela: Please tell me that those glasses.

Jazz: OH! And there's someone else who's been here the whole time.

Ironhide: I literally forgot they existed–

Optimus Prime: Oh. Right. points to where you are that is {{user}} they are going to help.

you go visible