Which Sigma Force Novel Comes First In The James Rollins Series?

The woman standing there was nobody that Scars had ever laid eyes on before, but holy God, he knew her. He knew her on a cellular level. In his blood. In his bones. In his heart and in his cock. He’d dreamed about her and he’d waited for her. He’d been looking for her forever, and now here she was. ** Six years ago, Zoe Parish fled Denver after a brutal encounter with a motorcycle club man, swearing never to trust one again. Now a mother and desperate to help her oldest friend, she returns when Wolf Connor promises his club is out of the life and she’ll be safe. Back in Denver, Zoe keeps her guard up, especially around Scars, whose effect on her is far more unsettling than she wants to admit. Vic “Scars” Innis has spent twenty-two years loyal to the Road Devils, earning his place as Vice-President. He thought he was content, until he meets Zoe. From the first look, he knows she’s the missing piece, even if she despises everything he represents. As danger closes in and an enemy threatens to destroy their fragile peace – and take Zoe’s child – Scars and Zoe are forced to confront their pasts and each other. The question is whether their bond will make them stronger… or finally tear them apart for good.

Elias has lived his whole life as a lie. Born a male Omega in a world where his kind are owned, traded, or bred, his only chance at freedom was to disappear behind a forged identity. Now he’s “Eli Arden,” Rank 2 at the most ruthless Alpha academy in the nation. No one suspects the truth; Not the instructors. Not the students. Not even the wolves who want to beat him. Only one person watches too closely. Ronan Vesper: Rank 1, cold-blooded, terrifying, heir to an Alpha dynasty—and the one Alpha Elias can’t afford to provoke… or attract. But suppressants are failing. Instincts are waking. And when Ronan catches Elias mid-dose, something shifts between hunter and prey. He should have exposed him. He didn’t. Now Ronan is circling him like a secret he wants to own. And Elias is running out of time to keep his body and identity under control. In a school where the weak are erased and the powerful take what they want… What happens when the deadliest Alpha discovers his greatest rival is an Omega?

I’m trained to do one thing: kill. I was put into a school where the concepts of love and forgiveness were treated as weaknesses. When I graduated, they told me I’d be lucky to survive; now I’m the best of the best and the person who gets the job done no matter what. I’ve assassinated Presidents, housewives, Navy SEALS and more shifters than I can count. I have more kills than anyone in my business, so when a new order comes in to kill Alpha Gideon, I take it without a second thought. ​He’s a job like any other, but during my scouting, I see something I’ve never seen before. Alpha Gideon isn’t a tyrant or a bully; he’s kind to his Pack. I start asking questions, which is when everything goes to shit. My signal is found, and for the first time in my life, my target has me in his sights. I expect pain and maybe even death, but Alpha Gideon treats me like a welcomed guest; his warmth and kindness open up something inside of me that I didn’t know I had. I should kill him before he changes me completely. I tell him I’m cold and heartless, and he laughs. Loving a mark has never been done, but no matter what I do, every touch sets me on fire and with each longing glance, my past becomes a distant memory. I’m ready to put everything I was aside to stay with Alpha Gideon when the call comes in; my fellow assassins have been called. The bounty on Alpha Gideon has been doubled. I have two choices: protect the man who has opened up my heart or kill the target and get the job done.

"Max DiSalvo gave his entire life to the SEALs. He would have married—he certainly enjoyed women—but he never could find one who understood his dedication to the Teams. It takes a certain caliber of woman to be a SEAL wife. Now, at 48, he is out of the SEALs, running his own commercial fishing company in Maine where he grew up, and waiting for his assignments from DHS.Regan Shaw, a SEAL widow, is an Intelligence Operations Specialist with DHS. Part of her job is analyzing information to assess threats, and she’s discovered a doozy—there is a secret group of very wealthy people who are smuggling terrorists into the country. And word has come down that a high-level member of the government is clearing the way for them.The group is about to have one of its executive meetings at an exclusive resort in Texas, and that’s where DHS is sending the two of them.SEAL Undercover is created by Desiree Holt, an EGlobal Creative Publishing signed author."

He entered the pack to bring it down. He never expected to fall for the Alpha sworn to destroy him. Silas Hati was raised on war stories. Trained to lie. Sent to the Red Moon to spy from the inside. But the moment he laid eyes on Alpha Ethan Lupa, dangerous, magnetic, cold, something shifted. The mission was simple: gather intel. Expose weakness. Bring Ethan to his knees. What Silas didn’t plan for was the tremor in his chest every time Ethan looked at him like he already belonged. As rivalries ignite and secrets unravel, Silas must choose to either: Destroy the man he’s starting to love, or destroy everything he was sent to protect.

Keeping her safe has become his life's mission. 
 Gage Hendrix is a man without roots. As an MSD Team Leader for the Department of State, he operates in high-threat environments. Serving in dangerous postings around the world, his team provides emergency security support and crisis response. Keeping the US ambassador's daughter safe in Sri Lanka? An unusual assignment for an "action group" used to dealing with evacuations, wars, incursions, and coups. Expecting a spoilt princess, Gage finds a hard-working therapist with a huge heart and sad eyes. 
 Hiding from heartache is no longer an option. 
 Chantal Durant's best friend has gone into hiding with intel that could lead to a nation's upheaval. Enemies have targeted the last person who helped her to escape… Turning a tragic past into a constructive existence, Chantal dedicates herself to helping others. She likes her work, likes her routine, and doesn't like that her safety is now in the hands of a cocky MSD agent. Her undeniable sexual attraction for the ruggedly handsome bodyguard would not only end his career but could get them both killed. 
 As multiple threats close in, Gage is faced with harrowing decisions. Trapped in an unfamiliar landscape, both Gage and Chantal will have to act fast to make it out alive. "If you're looking for the perfect blend of action and steam set against the backdrop of exciting international locales...your first stop should be Louise Dawn." - Janie Crouch.