In the simplest terms, Democratic Rep. Ron Barber faces a rematch with retired Air Force Col. Martha McSally, a Republican, in this highly competitive district based in Tucson, Ariz.

But over the past four years, this district’s story has proven anything but simple.

In 2010, the 2nd District served as the epicenter for tea party rage against the Democratic Party. The Democrat up for re-election that year, Rep. Gabrielle Giffords, beat the odds and won her race.

On the third day of her term in January 2011, Giffords was shot in a massacre in a local Safeway parking lot. Giffords, Barber and 11 others were injured, and six people died.

Giffords resigned in early 2012, prompting a June special election to succeed her. One of her top aides, Barber, won that special election. Aided by Giffords’ operatives, Barber went on to  defeat McSally, a top GOP recruit, by a narrow margin in November 2012.

A graduate of Harvard University’s Kennedy School of Government, McSally broke barriers during her time at the Air Force Academy. Republicans have hailed her as one of their best candidates of the cycle.

In 2014, Democrats are determined to hold onto the seat and Giffords’ legacy. Meanwhile, Republicans hope their vaunted recruit can alleviate some of the party’s difficulty appealing to female voters.

Editor’s note: Not all congressional races are created equal, and Roll Call’s politics desk admits to playing favorites. So in the spirit of the holidays, these are a few of our favorite things (races) to cover this cycle. We’re shining a spotlight on our 12 most fascinating races through the new year — in no particular order. Happy holidays from @RollCallPols!

Check out more fascinating races of 2014: California’s 31st District, California’s 17th District, Illinois’ 13th District,  Mississippi Senate and West Virginia’s 2nd District.