As Ari lies helpless in a coma in this week's Home And Away, Lewis, armed with a syringe, prepares to inject him with drugs that could kill him. Will anyone stop Lewis murdering Ari?
As if this is not shocking enough, the revelation that Lewis (Luke Arnold) is Ari's would-be killer means Lewis is the one responsible for the horror spate of deaths among Dr Christian's (Ditch Davey) patients at the hospital.
Last week, Christian made the decision to bring Ari (Rob Kipa-Williams) out of his coma after he was injured in a targeted hit-and-run.
That was after Lewis questioned Christian's ability to do his job, prompting the neurosurgeon to doubt himself. And this concerns fellow doctor – and his fiancée – Tori (Penny McNamee).
"Tori is worried that if Christian continues to doubt his abilities as a surgeon, he'll make errors in the operating theatre," Penny, 38, tells TV WEEK.
"She tried to gently remind him of this, but is forced to be quite assertive with him when he starts to spiral."
As fans know, Lewis and Christian have been at loggerheads over Lewis' insistence that Christian is to blame for the death in surgery of his wife Anna and their unborn child.
While they made an effort to patch up their differences, Lewis' simmering animosity has stymied any attempts to move forward so they can work together as hospital colleagues.
"Of course, Christian can see why Lewis is so upset about this tragedy," Ditch, 48, explains to TV WEEK.
"As a man who has always wanted a family, and now having the chance to start one with Tori and Grace, the impact is certainly not lost on him.
"He understands Lewis' pain, but he's adamant he did all he could to save Anna and her baby."
Tori and nurse Jasmine (Sam Frost) – who is now in a sizzling relationship with Lewis – are stuck in the middle of the men's feud.
Penny says Tori doesn't know what to make of unpredictable Lewis.
"He comes across as friendly and professional," she says.
"However, his temper and resistance to work with Christian prompts Tori to start doubting him."
But she has no clue Lewis is a secret killer who intends to do in poor Ari.
"Tori has no reason not to trust Lewis, so she gives him the benefit of the doubt," Penny explains.
As the Parata family comes together to talk about Christian's decision to bring Ari out of his coma, Lewis is in Ari's ICU room, preparing to insert the syringe into Ari's IV line.
Is it all over for Ari?