Lucas left alone with Jacob, what could go wrong

Transcription:
???: Go in!
Lucas: What's going on?
Finn: The monsters!
Lucas: The what?
Finn: Do you know how to swim?
Lucas: No?
Finn: It's safer if you stay here with Jacob.
Lucas: I don't understand!
Finn: Don't make any noise!

Characters:
Lucas (♂) : Arbrool (red)
Finn (♂) : Axaqueue (blue) with the orange hat
Elliott (♂) : Axaqueue (blue) with the red scarf
Alice (♀) : Axaqueue (blue) with the beads
Jacob (♂) : Etrikit (yellow)
Nancy (♀) : Axaqueue (blue) with the green hat