Danny and Steve 'welcome' new boss Ted Case into the UCOS office in Sasha's absence, but for all his wealth of experience, keen eye for detail and a killer instinct for detecting liars, they aren't quite as sold on his superstitious quirks.

The episode was rated 7.64 from 69 votes.

With Sasha back on fighting form, UCOS investigate the death of a talented cricket prodigy: star of the pitch and apple of his father's eye - yet loathed by his teammates. The death was recorded as misadventure, but with new evidence pointing to infighting, overzealous autograph hunters and extramarital affairs, UCOS are soon bowled over by the list of potential murder suspects. Wise to Steve's monetary problems, Danny appoints himself as personal financial advisor and enforces a strict no-frills, no-fun budget. But even with this distraction, he can't escape his own worries about revealing his relationship with Fiona to his ex-wife. Sasha cracks down on the boys' lacklustre fitness and reluctance to come to the 'cursed' Mum and Dad's Do.

The episode was rated 7.67 from 60 votes.

While Sasha is occupied with an intensive training course, the boys' investigations take them to a lookalike agency where the top two acts were found dead in an apparent double suicide 13 years before. In an industry reliant on the art of the illusion and their suspects intent on giving them the runaround, Ted, Steve and Danny are convinced there's more to this case than first meets the eye. Steve can't contain his excitement when their enquiries take them to the door of one of his football heroes - but his glee is short-lived when he remembers an expensive promised birthday gift. Sasha tries to instill discipline in her son Alex, and Danny and Fiona end up in a stalemate over their living situation.

The episode was rated 7.77 from 57 votes.

Ted leads an investigation into the apparent suicide of a city trader embroiled in the cut-throat world of London's financial district back in the '80s. With Ted capitalizing on his acting talents, the team delve deeper into the macho fraternity of 'the Wolfpack' and soon find a darker side to the debauchery, secret hand signals and all-nighters that bonded the traders together - including a strict hierarchy that might just be worth killing for. Sasha's nose is put out of joint when she returns to a different kind of boys' club, and Steve tries to learn some trade secrets on the job, amid his own financial crisis.

The episode was rated 7.79 from 78 votes.

UCOS investigate the murder of a private investigator, stabbed through the heart in a suspected robbery gone wrong. The answers may well lie within the victim's last three cases but it'll take the whole team's expertise to crack the codes within his mysterious notebook. The movements of a rare collectable stamp, The Russian Cousin, could hold the key to the whole investigation - if only UCOS could track it down. Steve rents out his flat to a pair of demanding, hot-tempered Italians and Ted is determined to avoid a trip to the doctor for fear of coming face to face with his own mortality.

The episode was rated 7.82 from 60 votes.

A skeleton uncovered in the foundations of a swimming pool is identified as Cheryl - a young, pretty lottery winner reported missing 17 years ago. UCOS' prime suspects are her quiz teammates, who won their lucky windfall as part of a syndicate. But while some have put their money to good use, the victim's boyfriend has fallen on hard times, and the media remain convinced he is the prime suspect in her murder. As allegations of affairs, fights and betrayal begin to surface, the team are left to ponder whether money really is the root of all evil. Sasha is set for a night in studying, but the boys have different plans and plot to set her up with Fiona's colleague Adam.

The episode was rated 7.86 from 64 votes.

A blood-stained bust is uncovered during some reconstruction work in a cemetery, pointing UCOS to the murder of an alternative medicine practitioner bludgeoned to death seven years ago. The evidence leads to the pioneering but controversial world of cryopreservation - the practice of keeping clinically dead patients frozen in time to extend their lives. In a sensitive case, with the watchful eyes of their bosses upon them, Sasha is determined that her team won't put a foot wrong. But with suspects constantly running rings around them and the sobering possibility that two perpetrators are still at large, UCOS must go out on a limb to unlock their most difficult cold case yet. Fiona is offered a job too good to be true in Aberdeen, leaving Danny bereft at the thought of losing her. Ted is devastated when he realises he's lost his lucky cigarette case, and Sasha has an interesting offer from the notoriously cut-throat assistant commissioner Cynthia Kline.

The episode was rated 7.91 from 66 votes.

In the ultimate series finale, UCOS are threatened with closure following their perceived mishandling of the Henway case. Their final case begins with the bloody murder of a political activist 15 years ago at the Madhouse - a hub for people with mental health issues. Just as the team are getting somewhere, the order comes from above for Ted, Danny and Steve to cease the investigation. But in true UCOS spirit, the boys throw away the rulebook and uncover something much bigger than just a straightforward murder, involving some top officials, a multinational drugs company and signs of a massive cover-up. Danny and Fiona's relationship hangs in the balance as she must give an answer to the job offer in Aberdeen, and Sasha is pulled into a game of political cat and mouse as she realises UCOS are merely puppets in Cynthia's game.

The episode was rated 7.95 from 58 votes.

As the detective drama returns, Gerry is spooked by the discovery of UCOS's latest victim - a cop, whose body has lain untouched under a basement for 30 years. As accusations of police corruption and underhand dealings begin to surface, Gerry has to face up to some skeletons in his own closet and it's a race against time for the team to help before his murky past catches up with him. While babysitting his grandson, Gerry becomes convinced that only he holds the key to the investigation and goes Awol to uncover the truth.

The episode was rated 8.10 from 80 votes.

Danny takes Gerry on the run as they search for the proof they need to prove his innocence - despite Gerry remaining tight-lipped about his involvement with dodgy dealings in his old unit. The stakes are high as the Unsolved Crime and Open Case Squad goes after one of the biggest crime families in London, and it's those closest to Gerry who are dangerously put in the firing line.

The episode was rated 8.16 from 75 votes.