I had originally planned a series of clues that would tie in old spy movie tropes.  None of these ideas panned out. One of the boys had received a loonie and a 1969 quarter – I was going to have him approach someone (somewhere) and require a spy pass phrase to get the next clue (“the chair is against the wall”, to which the reply must be “john has a long mustache”, at which point he would slide the 1969 quarter across the counter and the person would say “1969 was a good year” and he must respond “I wouldn’t know, I wasn’t born yet” and then receive the clue).

“The chair is against the wall. John has a long mustache” are, I believe, actual WWII radio code phrases delivered to personnel in occupied zones.  I first came across them in the movies “Red Dawn” and “The Longest Day”.

By the time the mystery was underway, I thought it was all a little too silly and too much to ask of the boys, so I dropped the idea. Other ideas that I left on the cutting-room floor:

– I was going to have the boys uncover a series of clues that led them to a payphone in town, where they would receive a call – unfortunately modern payphones block incoming calls;
– they would get an mp3 file with DTMF sounds (Dual Tone Multiple Frequencies), which they would need to play over a phone receiver and have it dial out automatically to another number without them knowing the number;
– I was going to incorporate something about numbers stations (here and here), but didn’t figure out how I would do this;
– I also tried incorporating some invisible writing, using lemon juice and paper and heat to reveal the message, but in my tests a hot light bulb didn’t work and I accidently set the paper on fire over the stove just as the message appeared.  I had a vision of setting someone’s house on fire, so I dropped this one.
– I thought about creating an acrostic code, but I felt like I had too many codes as it was, so this was also dropped;
– Finally, I had thought about having some messages in other languages, forcing the kids to look for a translator, but I never got around to this.

As for the actual next round of clues, another series of letters went out to the boys’ homes.

“Gather your friends. The curtain is raised. We are approaching the final problem.” Another allusion to Sherlock.
“Your friend has a locked container. To find the combination of the lock, gather all of your friends and go to …” a corner store in our neighbourhood, where I had arranged to have a pack of hockey cards left for the boys to purchase – the pack had been opened and the next clue sealed back inside.
“… the solution to unlocking the combination lock. Use a bright red marker, and do not make a mistake. We are on the heels of M. Take care, and gather all your friends …”

On one door step, I left a locked container with a combination lock. This one failed spectacularly. I chose 007 for the combination lock, thinking I could tie in James Bond, and hadn’t considered (!) that the boy would go through every combination in order. Took 5 seconds, whereas I had intended the clues to bring the boys together to solve for the combination. The combination number was to be solved with a maze puzzle I devised, and I ended up shifting it to the end of the mystery because they never bothered to solve the combination using the clues.

And finally, one boy received this note:

By now you should have discovered that we need to visit two locations on June 26th. The first is still uncertain to me. But I have learned its general whereabouts by a map triangulation.  
- s.h.

1. Craig Side Road & Donald B Munro Dr.
2. Carp Road & Holland Hill Road
3. Charlie’s Lane & Snelgrove Dr.

Not the actual concept of triangulation, but still … those street corners bring us to the largest landmark in the area – Diefenbunker.

This would eventually tie in nicely to the girls’ clues, once the streams came together, especially with the original jigsaw puzzle photo of the tunnel leading down to the bunker.

The “securely” locked container, once opened, contained a scrambled Rubik’s cube, on which were numbers and letters and times.

I designed this puzzle specifically for a boy that I knew could solve the cube quickly. The instruction was to solve it and read only the middle row around the cube. I was thrilled with this idea, but it turned out a little harder than anticipated because I overlooked the fact (hadn’t even thought it was possible) that the central square on each face of a Rubik’s cube can be in multiple orientations when solved, so the message was supposed to be oriented upwards for reading, but several squares were turned or upside down in the particular cube solution the boy found. Regardless, the eventual message was a geocode and time:

45°16’56.9″N 75°45’47.1″W 6:00pm

… which was the second location that they would need to visit on June 26th, and also previously hinted at in the jigsaw puzzle the girls had received.