I immediately recognized the familiar smell of the Thames. Déjà vu struck. Hadn't we done this dance already? Only then did I realize the river was on the wrong side of me.

The tunnel had taken us completely under the waterway. I looked across at London, wondering if Samuel was aware we'd escaped him yet. Best not to wait around and find out.

I turned to ask my friends what our next step would be only to find them arguing quietly amongst themselves in harsh whispers. ...