A story I couldn't help but compare to future ones that will use similar ideas - the shape-changing Zygons and the Master's Tissue Compression Eliminator came immediately to mind. Equally, for a story that was Ben and Polly's last one, they played very little part in the actual plot, and whilst a sudden goodbye hasn't been all that unusual for Classic Who it still felt rushed

Still, though, there was some nice intrigue going here, and I liked Samantha Briggs