Tobias discovers that Elfangor is his biological father in this episode. In the books, this was found out in #23, The Pretender.
Jake: Hey, Cass, what's up?
Cassie: Hey, well, I thought that with, uh, saving the world and everything, you probably hadn't had a chance to get anything to wear to the dance tonight.
Jake: Oh, Cassie, I totally forgot.
Cassie: No, it's okay. (pulls a box from behind her back)
Jake: What's this? (Jake opens the box to reveal a tuxedo)
Cassie: It was my grandfather's...he wore it to marry my grandma. It's been up in the attic ever since, and he was your size, so I thought that you could wear it.
Jake: Yeah. Cassie, this is amazing. We are going to be the best dressed couple at the dance. You know, except we're not really a couple, so it's...
Cassie: Exactly. Yeah.
Jake: We're just friends.
Jake: So, uh, do friends like us go for a capuccino?
Cassie: You mean like, with double foam?
Jake: Yeah, I mean like, with double foam and maybe some chocolate powder.
Cassie: I think friends like us do.
Hugo: It's okay, he's clean.
Tobias: What do you mean, clean?
Hugo: You're Yeerk-free.
Tobias: (scoffs) What's a Yeerk?
Hugo: You don't have to play dumb with us. We've all been there. We've all been a Controller.
Tobias: Yeah right. I'm outta here.
Boy: You don't have to be afraid of us, dude. We're not running on slug power anymore. We're the good guys.
Rachel: (in skunk morph) Well, that's the last time I wear THIS perfume to a dance.
Elfangor: This is a mental hologram. It was designed to deliver a message to my son.
Tobias: You have a son here on Earth? Where is he?
Elfangor: I'm looking at him. Yes, Tobias. I am your father.
Tobias: You can't be my father.
Elfangor: Your mother hid the truth from you, Tobias. To protect you. She wanted you never to feel that you were different. That you didn't belong.
Tobias: Why didn't you tell me this that night? When you landed here?
Elfangor: There wasn't time. When my ship was shot down by the Yeerk fleet, I had only enough strength to give the power of change to you and your friends. I hoped it would be enough to help you save yourselves...and your world.
Tobias: But...but I watched you die. I saw Visser Three turn into...some kind of monster...why? You must've known the Yeerks would find you. Why did you travel all the way to Earth and risk your lives for people you don't even know?
Elfangor: It was not for people I don't know. It was for the one that I do. I would gladly sacrifice forever with strangers for a single moment with someone I love.
Rachel: We only have a couple of hours together... I have a curfew tonight.
Tobias: I'll gladly sacrifice forever with strangers for a single moment with someone I love.
Rachel: That's beautiful... Shakespeare?
Tobias: My father.
Tobias: (voiceover) My name is Tobias. I used to think I was just a regular kid... you know, nothing special. But that's not true... it never was. My father was from another planet and he loved me so much that he risked his life to come here and save me. And now it's my turn... it's my responsibility to help save the world. I can't do it alone, but I have good friends and they're my family now. I might not know what's going to happen next, but I do know one thing for sure: together, somehow I know we're going to win.
This episode is narrated by Tobias, and it is his last time doing so.
Elfangor: Yes, Tobias. I am your father.
This line, whether intentionally or not, is a famous quote from Star Wars: Empire Strikes Back when Darth Vader says to Luke Skywalker: "Luke, I am your father."