
Clue 1
Prepare yourself, because solving this puzzle will take a lot of time.
Clue 2
It's also very "hands-on."
Solution
The lines represent clock hands which, when summed up, give numbers to convert. The second line, however, is upside-down to mirror the title text on the front of the card. The plaintext reads: "The Brothers Karamazov."
Clue 3
Clock-in, it's going to take a while.
Clue 4
If you can read a clock, then you're mostly there, but you may need a new perspective on the second line.

Clue 1
Have you solved your other stamps?
Solution
The numbers on the stamps give the plaintext: "For."

Clue 1
Have you solved your other stamps?
Solution
The numbers on the stamps give the plaintext: "For."

Clue 1
Prepare yourself, because solving this puzzle will take a lot of time.
Clue 2
It's also very "hands-on."
Solution
The lines represent clock hands which, when summed up, give numbers to convert. The second line, however, is upside-down to mirror the title text on the front of the card. The plaintext reads: "The Brothers Karamazov."
Clue 3
Clock-in, it's going to take a while.
Clue 4
If you can read a clock, then you're mostly there, but you may need a new perspective on the second line.

Clue 1
Have you solved your other stamps?
Solution
The numbers on the stamps give the plaintext: "For."