Sienna, played by Anna Passey, seems to be strangely fixated on the Osborne family and isn't happy to see Nancy's painkiller addiction grow ever more serious.
Full of spite, Sienna's first major attempt to cause trouble sees her trick Darren (Ashley Taylor Dawson) into finding Nancy's secret stash of pills. However, her efforts fail to pay off as Nancy (Jessica Fox) swears on Oscar's life that she's not taking them anymore.
Sienna is disgusted by Nancy's lies and then launches a second scheme against her. Finding Nancy asleep upstairs at the pub, Sienna switches on the iron and places it face-down on one of Oscar's babygrows.
As Sienna makes a hasty exit and smoke begins to engulf the room, she is unaware that Oscar is also upstairs at the pub and she has put the youngster in serious danger.
It's not long before Darren is alerted to the fire and he raises the alarm about Oscar. Sienna is horrified and rescues the baby while Darren concentrates on putting the fire out.
Sienna's cruel plot has the desired effect as Nancy is blamed for the fire. Darren also finds a stolen prescription pad and realises the extent of his wife's problem.
It looks like the Osbornes' marriage could be over as Darren struggles to forgive his partner, but he feels compelled to support Nancy when she receives the devastating news that her mother has been killed in a car accident in Canada.
As Nancy flies out to Canada to make the funeral arrangements, she asks Sienna to stay at the pub to help look after Darren and Oscar - opening the door for a long-running storyline which will see Sienna causing even more trouble for the Osbornes.
Hollyoaks airs these scenes on Monday, June 4 and Tuesday, June 5 at 6.30pm on Channel 4.
> 'Hollyoaks' Nikki Sanderson: 'Maxine, Blake's story is exciting'
> 'Hollyoaks' character to start fire in cruel scheme
> 'Hollyoaks' Anna Passey: 'Sienna is very misunderstood' - exclusive video
> 'Hollyoaks' Jessica Fox: 'New Nancy plot will be biggest yet' - exclusive video
> Read more 'Hollyoaks' spoilers and news
Over on Emmerdale, Debbie Dingle finds herself on the receiving end of Robbie Lawson's fury after giving him a taste of his own medicine.
Upcoming episodes see Robbie (Jamie Shelton) begin secretly stalking Debbie (Charley Webb) in a twisted attempt to get closer to her. Robbie knows that Debbie will want his protection if she feels under threat, especially as she is so isolated from her family at present.
Robbie attempts to make Debbie believe that her ruthless business contact Kirk is the one doing the stalking, but it doesn't take long for her to realise that Robbie is the real culprit.
Determined to teach Robbie a lesson, Debbie sets him off on a dodgy booze run before calling the police to report him. This leads to Robbie being arrested and undergoing police questioning.
Robbie is livid when he discovers that Debbie was the one who grassed him up, so he later heads round to her place and lunges violently at her.
Charity (Emma Atkins) is on hand to separate the pair, but she is appalled to see that little Sarah has witnessed the whole thing.
When Charity questions her daughter's recent behaviour and the effect it's having on her family, an unremorseful Debbie turns her back on her mother and her opinions. With Robbie hell-bent on revenge, has Debbie now lost everyone?
Emmerdale airs these scenes on Wednesday, June 5 at 7pm on ITV.
> 'Emmerdale' Jamie Shelton on stalker plot: 'Robbie isn't normal'
> Read more 'Emmerdale' spoilers and news
Coming up on Coronation Street, Maria Connor's relationship with Marcus Dent could be about to run into more trouble.
A difficult week for Marcus (Charlie Condou) begins when an old friend invites both him and Sean Tully to his wedding reception.
While Sean is looking forward to catching up with some old faces, Marcus isn't so keen as he wonders how his gay friends will react to the news that he's now dating a woman.
Marcus initially tries to avoid the awkward situation by failing to mention the invitation to his girlfriend, but this plan doesn't work when Sean lets it slip to Maria (Samia Ghadie).
As a result, Marcus and Maria end up attending the wedding after all, but it's clear throughout the day that Marcus is feeling uncomfortable.
Maria is quick to pick up on his unease, but will Marcus admit to his friends that Maria is his partner?
Coronation Street airs these scenes on Friday, June 7 at 7.30pm on ITV.
> 'Coronation Street' Charlie Condou: 'Dramas ahead for Marcus, Maria'
> Read more 'Coronation Street' spoilers and news
Meanwhile, EastEnders mechanic Dexter Hartman flies into a rage as his storyline with estranged father Sam James continues.
Sam recently arrived in Walford hoping to build a relationship with his son, but Dexter has so far snubbed his attempts at winning him over.
When Sam finds out about the refurbished car that Dexter and Jay are trying to sell at The Arches, he approaches Jay and offers up £1,000 for the vehicle.
Jay accepts the cash but decides not to tell Dexter (Khali Best) who the buyer was. However, Ava later finds out what's going on when she spots Jay handing paperwork to Sam.
Sam tells Ava that he's just trying to do a favour for his son, but when Dexter finds out, he storms off to The Arches and smashes up the car…
EastEnders airs these scenes on Thursday, June 6 at 7.30pm on BBC One.
> 'EastEnders': Khali Best goes behind the scenes - watch
> Read more 'EastEnders' spoilers and news
Coming up on Doctors, Al Haskey's interest in work colleague Jas Khella seems to be reaching unhealthy levels.
Al (Ian Midlane) has been harbouring a crush on Jas (Vineeta Rishi) for quite a while, but his feelings intensify as he starts orchestrating chances to bump into her so they can spend time together.
Having recently lost his aunt, it's clear that seeing Jas is the main thing keeping Al going at the moment.
Turning creepy, Al eavesdrops on Jas through her door at work as she makes a phone call. Hearing that she plans to attend a spin class, Al makes a note of the day and time in an obsessive attempt to monitor her routine. Will Al become sinister with Jas?
Doctors airs these scenes on Tuesday, June 4 at 1.45pm on BBC One.
> Read more 'Doctors' spoilers and news
Hollyoaks was the winner of our storyline poll last week as 45.8% of you chose Theresa pointing a gun at Dodger as the best plot.
Coronation Street came second with 39.4% for Tina's labour, while Emmerdale was third with 8.6% for the latest tension between Adam and Cain.
EastEnders took fourth with 4.1% for Sam and Ava's kiss, while Doctors was fifth with 2.1% for Zara and Daniel's D-Day.
Don't forget to vote in the poll below and let us know which storyline looks best this week:
Digital Spy Soap Scoop video - press play below to watch Amie Parker-Williams reveal gossip on Tina's labour scenes in Coronation Street, a baby bombshell in Emmerdale, danger for Dodger in Hollyoaks and a possible romantic reunion in EastEnders.