special delivery!
Sometime on April 21, an envelope containing a secret decoder ring would be delivered to David Fisher and Neil McLaughlin. Also in the envelope is a slip of paper with an encoded message.
F'J QDFKHFKC RFKKAO MZOQX. JZX 3, XAP LO KL?
-Miles Brennan
[The rings use the 'Zebras' cipher from the wikipedia page. It reads, presuming I encoded it correctly, 'I'm thinking dinner party. May 3, yes or no?']