Frank Hughes and Alex Urbina investigate crimes as part of their job in the United States Postal Inspection Service (USPIS), the federal law enforcement arm of the the United States Postal Service (USPS).
U.S Postal Inspectors are called in when a suburban couple are killed by a mail bomb. Suspicion immediately falls on the couple's estranged and heavily in debt son, who also just happens to be a Navy munitions expert. But investigations reveal that he is on the run from a past event in his life that is associated with the bombings.
Postal inspectors investigate a con man who uses the identities of others to falsify credit card purchases. Stealing credit card offers from mail boxes, he obtains cards in others' names, makes many purchases until the card is maxed out, but is always careful to pay minimum balances. According to the story, it is possible for individuals such as this to run many credit cards at a time without being caught.
