The POstables depart Denver for Washington, D.C. to attend the National Miss Special Delivery Pageant. After a brief stop at the site of Shane's childhood home, the four head on to their hotel. While checking in, they run into Phoebe and Parker, who have come to the nation's capital to seek out more answers about Randilynn. When the prospects look dim, Shane calls on her ex, Steve, for help.
Meanwhile, Rita checks into the pageant, and makes a friend in Mindy, Miss Wyoming.
For Randilynn, the second of two days passes, and she is forced to travel the rest of the way to the rendezvous point on foot.
The POstables, with Phoebe and Harper in toe, make their way to the National Postal Museum where Rita is making an appearance with other contestants. Oliver makes a return trip to the Pony Express exhibit for closure, inadvertently learning an important fact about Randilynn from Harper that later proves invaluable.
When Harper falls ill, Shane, Rita and Oliver have to keep the appointment with Steve at the Pentagon. While there it's revealed that not only may Randilynn Amidon be alive, she also sent a letter that proves the key to her rescue. The POstables waste no time in decoding the clues, and, once achieved, they contact Steve, who gets them an audience with Senate Subcommittee on Emerging Threats and Capability the following day.
The POstables appear before the Subcommittee to make their case. Though compelling, the committee is initially unwilling to send support, but Oliver's powerful final appeal, along with the fifth clue, proves the bump they need to convince the committee to reconsider.
Awaiting a decision, Steve attempts to appeal to Shane one more time to take him back, though Shane makes it clear where her heart truly lay.
Half a world away, Randilynn Amidon has made it to the rendezvous point, where she is finally rescued.
The POstables, along with Steve, Phoebe and Harper arrive at the tarmac the following morning, where Randilynn is reunited with her family.
Afterwards, Shane, Oliver, Rita and Norman prepare to head back to Denver, but not before making another stop at the site of Shane's childhood home, where it is revealed that Oliver has purchased the property with the intent to rebuild.