By Jessica Michele Herring (staff@latinospost.com) | First Posted: Sep 26, 2013 02:13 PM EDT

The second season of "Chicago Fire" did start off "with a bang," as promised by executive producer Derek Haas. In true firefighter form, the characters jumped right back into action, without a second to waste. 

"We're throwing everything at the audience," Haas told TVLine prior to the premiere. "There are four or five storylines going on, a lot of conflict. There's an outside threat to the firehouse - more than one, actually. One is physical, and one is mental." 

The four or five storylines in the new season were introduced in the opener, and they include baby drama, multiple romances and a new enemy. 

Sarah Shahi returned to complete the Renee/Severide storyline, which included her derailing Severide's (Taylor Kinney) baby plans with Shay (Lauren German).

"It's obviously going to... create a lot of trust issues," EP Danielle Gelber said. "Ultimately, you're going to find that it stretches Shay and Severide's relationship to the edge, and then like a rubber band, you'll see them come back together."  On the season premiere, Shay expressed to Severide that she has doubts that he's the father of Renee's baby, which caused Severide to storm out during their lunch. EP Michael Brandt said that the Severide/Shay/Renee story arc will be troublesome for a few more episodes. 

Although Dawson (Monica Raymund) and Mills (Charlie Barnett) call it quits this season and start seeing other people, they will still have love for each other. Nevertheless, Dawson will strike up a relationship with Casey (Jesse Spencer) later on in the season, which was hinted at in the season premiere. 

Dawson will also have a huge falling out with her best friend, Shay this season. "This rift that you'll see in Season 2, it does drive them apart for a while," Raymund told TVLine. "It certainly is probably the biggest fight we've gotten in so far, I would imagine. [It] is going to have enough of an effect to affect our work and our relationship at the house." But it probably won't drive them apart forever. "But I think Shay and Gabby are soulmates in terms of friends," Raymund added. 

There is also a new character taking charge at Firehouse 51. Michelle Forbes of "The Killing" joined the cast as Gail McLeod, a municipal consultant who riles the firefighters due to her new cost-cutting strategies in an effort to keep the firehouse afloat. "She comes in over Boden, and [due to] financial cutbacks in the department, Firehouse 51 - among others - is threatened for closure," Gelber said. "You see how that could potentially impact our guys. She will be a real thorn in their sides. But Boden, being the strong, stalwart chief, will try and take most of the heat and pressure on himself and let his guys do what they do best."

The sophomore season will also feature Molly's a lot more, as the beloved bar is now threatened by a bigger competitor, called Game Day. The gang will have to try their hardest to keep Molly's in business. "They're going to have to fight to keep it," Haas said. 

Check out "Chicago Fire" Tuesdays on NBC at 10 p.m. ET. 

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