Rebecca Ryan (played by Claire Goose) has been working as an undercover agent for the Organised Crime Division (OCD) posing as a taxi driver, while investigating London's south-side mob. When she finds her young daughter Lynn brutally murdered she fears her cover has been blown wide open, so she turns renegade and begins a brutal campaign of vengeance against the mob she believes killed her daughter. As she trawls the seedy depths of London's underworld hunting down her daughter's killers, the lines between good and evil, right and wrong begin to blur as do her notions of justice and revenge. It falls to the world-weary OCD agent Darius Cuise and his newly-assigned, hot-tempered partner Abby Barrett to track down Rebecca and bring her in before all hell breaks loose.
Not to be confused with Bad Days, the online series about fictional superheroes.
This movie contains examples of:
- Action Girl: Rebecca among others. She spends half the movie kicking ass and killing her enemies.
- Big Bad: Harry's sister Marla is pretty much the closest thing the movie has, being the most relishingly evil character and a bit of a stuck-up Alpha Bitch type who murders in cold blood. She's also Rebecca's toughest fight in the film.
- Black-and-Gray Morality: Rebecca becomes rather ruthless and cold in her quest to avenge her daughter's death, though the mob she is going after is still worse. The OCD agents who in turn chase after her aren't completely 'good' either.
- Catfight: Brutally subverted. There is plenty of girl on girl action, but it's also very brutal and bloody and not at all played for comedy.
- Combat Pragmatism: Rebecca is perfectly comfortable with resorting to dirty tactics to win a fight. She headbutts, blindsides, and even bites breasts if it means she will gain the advantage.
- Curb-Stomp Cushion: The girl who chases Rebecca into the back alley gets into a brief fight with her. While she gets a couple of decent hits in, Rebecca still comes out on top without too much of a struggle.
- Dark Action Girl: Marla, who's more or less the main villain of the film, is very much this trope. She kills one poor girl with nothing but her ruthlessness and brute strength, and even gives Rebecca a really tough fight in the climax.
- Designated Girl Fight: Rebecca has many people from both genders out to get her for one reason or another, but it's the other women who she ends up having one on one scuffles with.
- Hero Antagonist: Darius and Abby could be seen as this, since they're OCD agents who are working to bring Rebecca in before she goes too far.
- The Hunter Becomes the Hunted: Rebecca, who is on a mission to hunt down the mob that killed her daughter Lynn, in turn ends up being hunted down by a pair of agents.
- Girly Bruiser: Marla. She can put on quite a refined and elegant front when she wants to and wears lots of pink and lipstick, but she's a strong and brutal woman, as Rebecca and one other poor girl find out.
- Meaningful Name: Rebecca indeed has a bad day in this movie, much like its title implies.
- No-Holds-Barred Beatdown: Abby chases down and corners Rebecca in a quiet little private area. This was a big mistake on her part, as Rebecca dishes out one of these on her.
- Redemption Equals Death: Harry pulls this in the climax to save Rebecca.
- Red Oni, Blue Oni: The world-weary Darius is the blue to his new hot-tempered partner Abby's red. This is seen when Darius tries to call out to a fleeing Rebecca while Abby immediately pursues her.
- Roaring Rampage of Revenge: Rebecca goes on this throughout the movie as she seeks vengeance against those who killed her daughter.
- Starcrossed Lovers: In the sense that Harry turns out to be on the opposing side against Rebecca, although he ends up betraying them in an effort to save her, anyway, which ultimately results in his end.
- Tomboy and Girly Girl: Rebecca is the tough, serious and scrappy, scruffy hoodie and jeans wearing tomboy to Marla's girly girl, who wears pink and lots of jewellery, is a bit of a flamboyant Alpha Bitch at times, and has a very posh accent and pretend nice demeanour (except for when she turns violent on her victims).
- Unkempt Beauty: Rebecca, played by Claire Goose, spends most of the film running around in a dirty grey hoodie and jeans, with very messy hair and often some blood on her. She still looks quite appealing.
- Unskilled, but Strong: Marla is this compared to Rebecca. In their final fight, Rebecca displays better punching and kicking skill and more willingness to fight dirty and rough, but she struggles because Jade is clearly a physically stronger woman. She knocks Rebecca down multiple times in the fight, and Rebecca even has to resort to tit-biting to finally bring her down and finish her off.
- Use Your Head: Rebecca does this to Abby during their fight.
- Villain Protagonist: Rebecca edges on this trope at times, as she does become increasingly cold and ruthless out of desperation as the movie goes on.