You find the crescent shaped brooch on the adjacent chair where she was sitting. You take it to one of the baristas but he’s too busy to want to know. The back of the brooch is marked Samantha, Mornington Crescent. You decide to find Samantha and return it. Today’s good turn.

In the street you ask directions.

“Mornington Crescent? Sorry mate, I’m not from round here.”

“Mornington Crescent? Yes, now let me see… It’s um…No, it’s gone. ‘fraid I can’t help you there.”

“Mornington Crescent? I am sorry, I haven’t a clue.”

“Your best bet is the tube. Take the northbound tube from Euston and it’s your next stop.”

You return to Euston station and take a train promising High Barnet on its front. You arrive at Camden Town without apparently passing through Mornington Crescent. Maybe you dozed? Maybe the station is the invention of a devious panel game creator?

You see a sign for southbound trains to Euston. Hearing a train approaching you rush downstairs and hurl yourself aboard as the doors close. Breathing heavily, you stand by the doors, peering out of the windows, fearful of missing your stop. But miss it you do. You’re back at Euston. Did you blink?

Another northbound tube, this one promising Edgware. You take it arriving back, minutes later, at Camden Town. You look at a tube map. Mornington Crescent does lie between Euston and Camden but only on the Charing Cross branch of the Northern line. Mystery solved. You decide to walk.

You arrive at Mornington Crescent. There’s a pub on the corner, The Lyttleton Arms. You enter, order a pint and take it outside. You sit down at a table with a commanding view of the crescent. You feel Samantha’s brooch in your pocket and wait.