The girls are back in town! The girls are back in town!

The town is Derry (“or Londonderry, depending on your persuasion – a troubled little corner in the north-west of Ireland” as Erin records with customary flair for the dramatic in her diary) and the girls are the quartet of best friends who live there; our diarist Erin, her offbeat cousin Orla, Clare (permanently anxious and probably gay, even though Erin “doesn’t believe in lesbians”) and Michelle, who is basically a pure id with a perm, all attend the same Catholic girls’ school. So too, for reasons we won’t get into here, does Michelle’s despised cousin James, over from England.

A second series about their teenage travails set in the 90s against the backdrop of the Troubles was commissioned as soon as the first episode of Lisa McGee’s hysterically funny and occasionally profoundly moving creation was broadcast last year. As it finally reached our screens, we found the girls caught up in a bridge-building school overnight trip – arranged by Father Peter, in whom they induced a crisis of faith last series and who has taken a ‘sabbatical’ with a hairdresser, been dumped and returned to the priesthood since we last saw him – to mingle with the people who call it Londonderry. Where English teens might cross the Channel to experience other cultures, the Derry girls need only travel to a draughty town hall to meet Protestants.

Name badges on, they are told to pair off. “Sister Michael!” cries Orla. “I don’t have a Protestant!” “You’ll just have to share with James,” Sister Michael tells her. “There aren’t enough Protestants to go round.”

Father Peter is keen to get them to concentrate on their similarities. Can any of the students think of anything Catholics and Protestants have in common? “Catholics really buzz off statues and we don’t so much” shouts one not of the convent’s number. The good father points out that this is a difference. They try again, repeatedly. The blackboard for similarities remains stubbornly empty while the differences board covers every facet of life, from “Protestants don’t like Abba” to “Protestants keep toasters in cupboards.”

Facebook Twitter Pinterest Spare a thought for Father Peter ... Derry Girls. Photograph: Peter Marley/Channel 4

One secret party that night (nerdy Jenny-with-the-trust-fund dobs them in – “You will go far in life, Jenny,” Sister Michael tells her informant, “But you will not be well liked”) and an equally disastrous attempt at abseiling later and both sets of parents are called. The experiment is over. Back to your toaster cupboards and your statues, kids. And spare a thought for Father Peter, who was only doing his best. Desperate.

It was more than enough to reassure everyone that the Derry Girls’ magic remains intact. The evocation of the 90s is as lightly done as ever (Elizabeth Hurley is fleetingly referenced – “She’s a total ride but she paperclips her frocks together”) and the Troubled setting, even when the division is brought unusually to the fore, never overwhelms but simply throws into relief the ordinariness of the girls’ lives in the middle of extraordinary depths of conflict. Meanwhile, the story unfolding back home about why – why? Why? – Michelle’s mother doesn’t want her big bowl – her big bowl! – back from Erin’s is one to bind us all.

The new series retains all the unmistakeable, genuine flavour of teenage life, and does that rare thing of concentrating on all that was good about being an adolescent girl. Instead of the inner torments, it showcases the overwhelming confidence that somehow co-existed in equal proportion to the angst. The unabashed sexual curiosity (remember Michelle last series reckoning the time was ripe “to lose the rest of my virginity”) alongside the nervousness (“I haven’t put the hours in,” explains Erin to ‘her’ Protestant boy she is convinced is about to unleash his sophisticated moves on her, “It’s just not part of our culture, but if you’re okay with that I say we just crack on”). And above all, the sheer volume at which life was lived. No half measures, no doubts (for long), no second-guessing, just a headlong, passionate rush at everything until the day you find yourself exhausted and unwittingly embark on the long, inexorable journey towards the Sister Michael state of mind in which you will end your days. You may not actually take the veil, but life in a nunnery will start to hold attractions you never dreamed of when it was still your gang hanging tight against the world.