After their mother Linda died in a car crash, their father Jack sent Steve and Mary to the mainland.
Steve got shipped off to Grandma McGarrett's place, in the rural Midwest. She was very elderly by then, or so it seemed to his 15-year-old self, but she did her best to look after him. His grandmother spoke a lot about her husband, who was killed at Pearl Harbor, and how bravely their son Jack had served during Vietnam.
Her stories helped spur Steve to follow in their footsteps, and join the Navy. And to be honest, living so far inland made him feel marooned...trapped, even. At least Annapolis was by the ocean.
Mary, meanwhile, wound up with her mother's younger sister in the New Jersey suburbs. They'd only ever met a few times before, since flights between Hawaii and the East Coast were so expensive. Aunt Annie was a single woman in her early 40s and had no kids of her own, so it was a steep learning curve – one hell of a bumpy ride, to be honest.
But both of them had loved Linda, and swapping stories about her (Annie's memories of their shared childhood, Mary's memories of her own) helped them to cope. It took a long time, but they cried and laughed and healed together.
Still...Mary was a teenage girl, neglected by her workaholic father, bereaved of her wonderful mother, and ripped from her lifelong home. Things could have turned out pretty badly for her, if it wasn't for her aunt. Annie's support kept Mary from going off the rails – running away to the city, breaking the law, hitting the bottle, all that kind of stuff.
She stayed in Jersey and graduated from high school with decent grades, but didn't feel like college was for her. Unsure of what to do with her life, Mary worked retail for a few years. Then, bored by the daily grind, she decided to take a bartending course at night school.
And to her surprise, it turned out she was really good at bar work. Mary had a knack for creating drinks, she never cracked under the pressure of happy hour or game night, and she could even do those fancy tricks like Tom Cruise in Cocktail.
As well as that technical stuff, she had a talent for the psychological aspect of bartending. Mary was a sympathetic listener, but could give patrons tough-love advice when needed – more than one wife had called to thank Mary for talking sense into her repentant husband. And she'd send regulars home, in a cab, before they reached tipping point.
It was while Mary was working in Weehawken that she crossed paths with a cop named Danny Williams.
Now, maybe the location for their fateful encounter was a great Irish pub in Danny's neighborhood, where he liked to have a couple of beers at the end of his shift. Or maybe it was a scuzzy dive in his patrol district, and Danny came in on official business: there was a massive brawl, or the bar's owner was crooked and got arrested.
...whatever. The point is, as soon as Mary and Danny met, the sparks just flew. She was snarky and didn't take shit from anyone; he was talkative and funny. They both loved hard rock and Italian food and trashy sci-fi movies, but they argued about pretty much everything else.
It was a good thing they were both single at the time, because instant chemistry like that? Damn hard to deny.
To cut a long story short: they fell in love, Danny proposed, they got married, and Mary got pregnant. They moved to Newark, to be closer to her Aunt Annie and to his extended family, and got a little two-bedroom place. It wasn't much, but they were happy enough.
Once they found out they were having a girl, the great naming debate started. Mary wanted to name their baby after her mother, Linda, while Danny thought Grace would be the perfect choice. It was his grandmother's name, sure, but he also thought that greeting his pregnant wife by saying "Hail Mary, full of Grace" was fucking hilarious.
He soon stopped doing that, because Mary's usual tolerance of his wisecracks was severely diminished by morning sickness and swollen ankles. But the name stuck, somehow, and she really grew to like it.
Danny found himself reciting the Hail Mary for real, over and over, after she went into premature labor. And when his daughter was born healthy and beautiful, he thanked his Mary, the Virgin Mary, God, Jesus, and every saint he could remember.
So Grace Linda Williams came into the world, and was loved and treasured by both her parents. But gradually, Mary and Danny grew apart. It definitely didn't help that he clocked up long hours, while she was home alone with the baby. She was the daughter of a cop and she'd always known the risks of police work, but that didn't stop her worrying about her husband every day.
And once Grace was a few years older, Mary went back to bartending Friday and Saturday nights to help pay the bills. The money was a big help, but she and Danny got so out of sync that they barely had any quality time together. They argued more, and rarely laughed. It became harder and harder to remember why they'd fallen for each other in the first place.
They eventually separated when Grace was seven, figuring they weren't doing her any favors by sticking with a loveless, tension-filled marriage. It wasn't a spectacular explosion or anything; nobody cheated, nobody screamed, and nobody got kicked to the curb. They stayed friends, genuinely and not just for Grace's sake, but the romance was gone forever.
Mary got increasingly homesick after they split up, and there was less and less to keep her in Jersey. Being surrounded by Danny's family was no longer a positive, seeing as they blamed her for breaking his heart. And Annie was gone – she'd met a wonderful woman online, and after a two-year LDR had moved to Boston to be with her.
But it was her father's brutal murder and Steve's unexpected decision to stay in Hawaii afterwards that finally spurred Mary to go home. She'd seen her brother maybe a dozen times over the last two decades, mostly brief weekend trips while he was studying at Annapolis and later stationed in Virginia. She loved him, and deeply regretted all the years they'd lost. Mary didn't want Grace to grow up not knowing her awesome uncle.
For his part, Steve was delighted that his sister was coming back. Mary was almost the only family he had left, and he really wanted to be part of little Gracie's life as well. And their parents' house was too big just for him; Steve didn't believe in ghosts, but the place was filled with bittersweet memories that haunted him all the same.
Danny wasn't exactly overjoyed about Mary's plan, but agreed to go to Hawaii with her. Maybe Danny's mom never stopped chastising him for walking away from his marriage vows; maybe his brother Matt had already suffered a spectacular downfall, either arrested for massive fraud or escaping New York with the FBI on his tail. Whatever the reason, Danny left Jersey in a more optimistic frame of mind than anyone might have expected.
So a few months after Steve came home, Mary and Grace moved into the house with him and Danny rented a small apartment nearby.
Grace quickly adapted to her new surroundings, and seemed to blossom before their eyes. She started at public school, made friends, and Hawaiian and pidgin words soon peppered her vocabulary. She even learned to surf from Mamo, who'd taught her mother and uncle so long ago.
Mary took a lunchtime shift at Honolulu's oldest Irish pub, which didn't get so many tourists as other, flashier bars. She became a favorite of the daytime regulars, some of whom had known her father. Mary had only faded childhood memories of Jack, so hearing their stories was an educational experience: sometimes emotional, sometimes hilarious.
And Danny? He joined the Honolulu PD as a homicide detective, but had real trouble fitting in. Mary had prepared him for island life as best she could, and he attempted to follow – or at least respect – the Hawaiian way of doing things. Hell, he even quit wearing a tie to work.
But his partner Kaleo was openly hostile, calling him a "fucking haole" to his face, and the brass refused to reassign him. The rest of the squad hardly made Danny feel welcome, either. Although he tried to hide it from Mary and Grace, he was lonely and unhappy.
Steve had already established the Governor's Five-0 taskforce by then, getting his start by poaching Meka Hanamoa – the detective investigating Jack's murder – from HPD. Meka was still a young guy, but whip smart; he knew Oahu inside out, and he didn't treat Steve like an ignorant mainlander.
Then Steve took Chin Ho Kelly on for his considerable experience as a detective, ignoring the taint of his supposed corruption. And he added Chin's rookie cousin Kono Kalakaua to the team for her instincts, her fearlessness, and her fantastic right cross.
As Five-0 got busier, handling more and more cases, Danny was the obvious person for Steve to hire next. Mary had no objection; in fact, she was quite happy to have her brother and ex-husband team up, not least because they could look out for each other. The two of them said nothing against the idea, either, but both secretly had very mixed feelings about working together.
Because Steve always had a thing for Danny, and Danny always had a thing for Steve.
They'd met the week before Mary and Danny's wedding, nine years earlier, and had their own version of immediate, overwhelming attraction. Steve was bisexual but deeply closeted, what with DADT and all, so his heart sank when he saw how hot his sister's fiancé was. It got even worse as he realized that Danny was smart and funny and an all-round great guy. Steve cursed himself for being a terrible brother, and had a lot of cold showers.
Danny, though, had never really been interested in men. Well, okay, there were some teenage fantasies and some surreptitious locker room glances, but he considered himself straight. So he didn't initially understand this magnetic pull he was feeling.
When Danny dreamed about his fiancée's brother the night before the wedding, he freaked the fuck out – ashamed, confused, and afraid. He was polite to Steve on the day, but held back from that joking banter they'd started up within minutes of being introduced. And Danny breathed a sigh of relief when Steve left the wedding early to return to base.
Steve didn't come back to Jersey for nearly two years – his SEAL duties had kept him away, but so had his memories of his brother-in-law. When he showed up for Grace's first birthday, both he and Danny were privately dismayed to find that nothing had changed. The two of them were still drawn together, still clicking on every level, and it kept happening every time Steve visited.
Neither Danny nor Steve would ever have acted on it, of course, because they were honorable men who wouldn't betray Mary like that. Anyway, neither knew how the other felt.