In episode four, Derry is welcoming the 'Children of Chernobyl' - teenagers, affected by the Chernobyl nuclear disaster, who have been sent from their contaminated homeland for a few weeks of fresh air to, as Sister Michael puts it 'give their wee lungs a clear out'. The Quinns are hosts to one of these 'children' - Katya. Erin couldn't be more excited - she can't wait to share her wisdom and benevolence with this 'poor Ukranian girl'. Katya, however, turns out to be sophisticated, confident, sexy and a lot less grateful to be in Derry than Erin had expected, unless you factor in one of the gang. Meanwhile the rest of the family has other preoccupations - a new development in Granda Joe's love life leaves his daughters deeply unimpressed.