It looks like the net is finally closing in on Professor Gaskell and his risky stem cell trial next week, leading to a dramatic showdown between him and Holby bigwig Henrik Hanssen.

After learning Gaskell (Paul McGann) has been operating on patients – including her – using faulty implants, surgeon Jac Naylor wants hers removed from her spine. But Hanssen, unaware of the risks Gaskell’s been taking, thinks Jac’s being irrational and gives Gaskell and the trial his full support.

Hanssen eventually agrees to let Jac’s op go ahead and assists Gaskell in theatre. At the same time, however, medic Meena confides in Sacha about the suspicious circumstances surrounding surgeon Roxanna’s death – and he secretly tells Hanssen!

With all of Holby’s senior staff now fearing Gaskell’s lost the plot, they break into his wet lab. There’s no Gaskell but Sacha, Ric, Fletch and Hanssen are disturbed by what they find there and Hanssen is exposed to danger when he accidentally puts his hand in a poisonous substance…

Knowing he has to find Gaskell and stop the madness, a hallucinating Hanssen tracks Gaskell down to a nearby lake and, as an intense stand-off ensues, unbearable truths are revealed…

With Gaskell edging closer towards the lake and Hanssen deteriorating from the poison, is one of them going to die?

Holby City continues Tuesdays at 8pm on BBC1.