"It's important to take special care of all your weapons, so they never fail you," Ingress says, repeating the mantra from more than one of her tutors.

She sits down on the grass beside Havelock, careful to point the knife away from her. "I'm tired. Do you mind if we stop a little early?"

She's not physically tired, even though the lesson has been going on a for a good length. Her mind, on the other hand, is a little heavy with thoughts.