Democratic Sen. John Walsh (right) and his son Michael leave the Old Senate Chamber on Capitol Hill in Washington in February. (Lauren Victoria Burke/AP)

This post has been updated 

More than 100 Democratic activists in Montana gathered in Helena on Saturday, where they nominated state Rep. Amanda Curtis for the U.S. Senate at a hastily arranged convention. She will face Rep. Steve Daines, the Republican nominee and front-runner.

So exactly why did Montana Democrats do this after they already held a primary in June? And how did it all work? We're glad you asked! Below is everything you need to know.

Okay, so why did this happen? 

Because Sen. John Walsh, who won the Democratic nomination in June, dropped out last week. Walsh, who was appointed to the Senate in February, faced allegations he had plagiarized a substantial portion of a paper he submitted at the U.S. Army War College. That derailed his campaign. And he could have hurt other Democrats on the ticket. That's why he bowed out.

Got it. How did the convention work?

Members of the party's State Central Committee gathered Saturday morning at the Lewis & Clark County Fairgrounds. Two people were officially put forward as possible nominees by the delegates: Curtis and rancher Dirk Adams. They both gave speeches. Then the delegates voted, choosing Curtis.

So who is Curtis?

Curtis, 34, is a math teacher. She has served in the state House since 2013. She's not a household name in state politics.

Will Curtis have a chance of winning in November?

She has a chance, but not a good one. Democrats have probably put themselves in a better position than they would have been in with Walsh. But the reality is that Curtis is not a top-tier recruit. (More prominent Democrats such as former governor Brian Schweitzer declined to run in Walsh's place.) She will have little time to introduce herself to the state. And Daines is expected to have a huge fundraising advantage. Montana is a conservative state -- Republicans appeared to have the upper hand here even before and during the time Walsh was the nominee. Now, they are really in the driver's seat.

What does it mean in the battle for the Senate majority?

The entire Walsh scandal and scramble to replace him have bolstered Republicans' quest to win back the majority. They need to gain six seats to do so. Montana is one of three open seats ripe for GOP pickups. The contest looks pretty secure for Republicans now. And since Daines is not expected to face tough competition from Curtis, it means Republican groups can focus their money on other key contests.