Steve McDonald and Leanne Battersby receive the earth-shattering news that Oliver's mitochondrial disease is incurable.
As the family and the rest of the street reels from the news, everyone struggles to process their grief.
Simon Barlow is hurt by an overheard comment by Leanne and Peter Barlow invites Simon to move in with him, leaving Nick Tilsley furious.
Emma Brooker turns to Alina Pop for comfort while Alina squirms about going behind her back with Seb Franklin.
Toyah Battersby and Imran Habeeb decide to put their fostering plans on hold, and Evelyn Plummer isn't happy about Arthur's blossoming friendship with Roy Cropper.
CHECK OUT: Coronation Street Monday 29 June - Friday 3 July
Coronation Street Monday 29 June - Friday 3 July
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Steve and Leanne meet with the consultant who tells them Oliver has an incurable form of Mitochondrial disease. A distraught Leanne demands a second opinion.
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Meanwhile Toyah and Imran have been making headway on their fostering application but when news of Oliver's diagnosis reaches Toyah, she's conflicted.
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Toyah doesn't think that now is a good time to foster a child with her sister in such turmoil, but Imran urges her to gently test the water before ditching their plans.
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Toyah goes to visit Leanne and is struck by how badly Leanne is coping with the diagnosis, and realises there's no way she can raise the subject of fostering.
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An utterly distraught Leanne explains that Oliver is all she ever wanted and that she couldn't cope if he died... not realising that Simon has overheard the whole thing.
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The next day Simon has an exam to sit but, still stung by Leanne's words, when he arrives at school he decides to act out and not take it.
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Later on, a hurt Simon confides in Peter about what he heard Leanne saying and Peter invites him to come and live with him and Carla for a while.
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When Nick later bumps into Peter on the street he rails at him accuses him of taking Simon away from Leanne when she's at her most vulnerable.
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But when Peter delivers the news that Simon knows what Leanne said, she's apologetic - but it's not enough to stop Simon from going to stay with his dad anyway.
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With the future of his family uncertain, Nick decides to apologise to Peter and finds himself being unexpectedly comforted by his nemesis.
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Elsewhere, Emma is also struggling to process the diagnosis. After Alina helps her with her injured hand, Emma breaks down about Oliver.
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Alina does her best to comfort Emma. Later on, Alina calls Seb to cancel their drink, saying she doesn't want to sneak around behind Emma's back, and requests he not ask her out again.
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Rob and Arthur head for a lunch date at the café and Evelyn is taken aback when Arthur and Roy get on a little too well, discussing their shared love of steam trains.
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When Roy invites Arthur to come by later to discuss trains some more, Arthur is enthusiastic while Evelyn fakes a smile. Later on Arthur apologises to Evelyn for coming on too strong earlier.
WATCH: Marcel Somerville reveals E4's 'Celebrity Come Dine with Me' filming finished at 2am most nights
But before all that, here's what's coming up this week on Corrie...
With Shona Ramsay back in Weatherfield staying with Roy Cropper, David is hopeful that they can reconcile their relationship.
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But when Shona decides to give him a chance and invites him over for pizza, David is caught off guard when she comes on a little strong and, embarrassed, Shona kicks him out.
Is it over between them for a second time?
Meanwhile, Seb Franklin tells Alina Pop that he still has feelings for her, but wanting to spare Emma Brooke's feelings, Alina says they can only be friends.
Carla Connor asks Pete Barlow where he was the night of a recent assault and Leanne Battersby takes Oliver Battersby to the petting zoo.
When is Coronation Street on TV?
Corrie has stripped back to three single episodes a week: Monday, Wednesday and Friday at 7:30pm on ITV.