You're Surcouf, and your radar just pinged something...something close. You disentangle yourself from a sleeping Mary, waking her in the process, and quickly head to the surface for a visual. It's too far away for a human to make out, but...
Mary arrives on the surface shortly after you do, yawning deeply while you stare into the distance, "What's wrong?"
You hesitate for a moment, "I think I can see a cruise liner."
Without warning, you feel May's hand close around your arm like a vice, drawing your gaze to her own wide eyes, "Then we need to hurry! No one's ever come this close before! We need to go right now!"