Chapter One:

Disclaimer: All publicly recognizable characters, settings, etc. are the property of their respective owners. The original characters and plot are the property of the author. The author is in no way associated with the owners, creators, or producers of any media franchise. No copyright infringement is intended.

Spoiler Warning: Possible spoilers up through the season 3 finale.

Andrew Marlowe said that for season four of Castle they would be 'moving the island', and highlighting more conflict. So what the heck, I thought I'd give it a try. I've followed the light, fluffy Dating series with a sequel built around the Castle theme. This first will explore his premise in my universe – that a loving relationship between two people as strong willed, deep and multifaceted as these two would have rough spots and dark times.

The first story picks up approximately 3 months into their marriage. Remember, the finale didn't happen, so Kate was not shot and the Captain is still alive. Consider this your warning: all is not warm and fuzzy for our couple. There are definitely some 'Cracks in the Castle'. Enjoy!

This is not what I meant when I told Castle I wanted someone to dive in with me," a frustrated Kate Beckett grumbled to herself. She got out of the squad car, pulled up her coat collar against the wind and approached the grizzly murder scene. She looked uncharacteristically frazzled, somewhat pale, and every bit five months pregnant with twins.

She walked at a fast pace, knowing that she was late because her morning gynecological appointment had run way over. She saw Lanie, Esposito, Ryan and several uniforms all gathered around the bloodied body, which was lying naked in the dark, dingy New York ally. They looked slightly annoyed and definitely cold, and she regretted that she had kept them waiting for over an hour in the harsh December weather.

As she drew near, Kate felt her stomach doing cartwheels, and realized that the smell of the partially decomposed body was not mixing well with her pregnancy hormones. She glanced at Lanie, who immediately saw the distress in her eyes, and lurched behind the nearby dumpster to puke.

"Classy, Beckett, real classy," she chided herself as she wiped her mouth with a tissue, took a deep breath and turned back to the crime scene, trying desperately to look professional despite having just tossed her cookies in the ally.

As she approached the scene, Kate noticed the two young uniform officers smirking to themselves, no doubt amused at seeing a veteran homicide detective in such a predicament. "Could this day get any worse?" she sighed. Just then her cell phone rang. She looked and saw that it was Castle, calling for at least the tenth time this morning.

Kate angrily turned her back to the group and whispered into the phone. "Castle, will you quit calling me! I'm at a crime scene!"

Castle was pleading. "Kate, you promised me you'd call after the appointment! What did the doctor…hello? Kate! Don't hang up! Kate, please!" It was Castle's turn to be angry.

Kate shoved the phone in her pocket and turned back to rejoin her team. "So Lanie, what have we got here?" She said briskly, attempting to sound calm and assertive, despite her embarrassing entrance.

"Well, it looks like the vic was…" The ringing of her own phone interrupted Lanie. She glanced at it and then looked at Kate, slightly bewildered. "It's Castle," she whispered.

"Shit! Don't answer it, Lanie," Kate ordered through gritted teeth, clearly annoyed. She suddenly caught another whiff of the body and was forced to immediately pivot and unceremoniously throw up again, this time on poor Ryan's shoes, who had made the unfortunate decision to stand behind her.

Kate cringed in horror at what had just happened, the look on Ryan's face making her feel even worse. She tried to apologize and leaned down to try and help him clean off his shoes, only to have her cell phone start ringing, yet again.

At that moment, Kate Beckett was still nauseous, totally exhausted, extremely embarrassed, and absolutely sure of one thing: when she got home, she was going to kill Richard Castle.

Truthfully, their married life had started on a downward spiral rather quickly. The euphoria over Kate's pregnancy was soon replaced by the somber reality that it was going to be an extremely difficult one. Kate had constant morning sickness that often lasted all day; she suffered from frequent headaches and had horrible mood swings. Her anger inevitably was directed at poor Rick, who did his best to dodge her wrath, monitor her fragile health and deal with all of the complications of their new marriage, including moving Kate into the loft, financial matters, preparing for the birth of twins and a thousand other decisions associated with blending two complex lives into one. Rick was also deeply hurt by Kate's decision not to take his last name even in hyphenated form, insisting that it would draw too much attention to her work as a detective.

While these things were all challenging, for a couple in love as much as Castle and Beckett they would have been nothing more than trivial irritations. However, Kate's absolute insistence on continuing to work as a homicide detective during her pregnancy was anything but a minor issue. To complicate things even further, the police commissioner had issued the ultimatum that Castle was not permitted to continue shadowing her once they were married.

This arrangement did not go well. Each morning as Kate was getting ready for work, her stomach queasy and her nerves frayed, Rick would hover over her, obsessing about her health, eating habits, morning sickness issues, need for sleep, etc. This of course irritated the hell out of independent-minded Kate, causing her morning mood to turn surly even before she had left the loft.

Once Kate left for work, Rick obsessed about her. He couldn't stop thinking about her safety, the health of the twins, her medical complications, and the day-to-day dangers her job entailed. He was soon unable to write, spending hours staring at the laptop screen. His eating habits became erratic, and he was compulsive about checking up on Kate, calling and texting her up to fifty times a day. When Kate refused to answer his harassing calls, he began calling Ryan and Esposito. He became such an ongoing distraction for the pair that the Captain made them block Castle's cell number on their phones.

His nightmares started after Kate's sonogram confirmed it was twins, which they had already known in their hearts but had not shared with anyone else. Castle would wake up in a cold sweat, having dreamed of Kate getting injured or sometimes even killed on the job. He would be a wreck; pale, shaking and emotionally devastated after a particularly bad nightmare. Last week Rick had dreamed that she was shot in the abdomen, and he had been inconsolable the rest of the night. Kate was actually starting to worry about his physical health, as lack of sleep, loss of appetite and constant stress were taking their toll on him.

All in all, their first three months of marriage for the Castles had been pretty much been a living hell. And for Kate, standing in the cold alley watching Kevin Ryan attempt to clean off his shoes with handfuls of soot-covered snow, her phone beeping that it had another incoming message, tonight might just be the breaking point.