In this episode, Steve and Blue get prepared for Mailbox's Birthday. Mailbox has just turned a decade old.
For Mailbox's birthday, there's a special celebration and we are invited to help out. They help decorate the cake for the party by observing patterns. They also skidoo along with Steve and Blue into the present store. There, they find the perfect present for Mailbox, which is a stamp book and then help Blue & Steve to find it when it gets lost among a bunch of other presents.
This is the first episode in which Mailbox's voice actor Seth O'Hickory is credited in the closing credits to this episode.
Steve's rugby shirt near the end of the episode seems to have a slight color alteration, as if the darker green stripes appear to be blueish-greenish.
Since Mailbox was ten years old in this episode, we know that he was born in 1986, and nine years old in the first two episodes. By the end of the series, he should be eighteen years old as of the Season Six episode Bluestock.
Steve gets interrupted trying to figure out the answer to Blue's Clues with two clues by Tickety getting his attention to tell him something.