Single dad George Stevenson builds a rocket to send his wife's ashes into space but he's brought down to earth when the launch ends disastrously. Though determined to try again, he is forced to realise his promise to Bethan is getting in the way of being a proper parent. Can he walk away from his dreams?

After a day's work on the production line at Blossom's Chocolate Factory, George returns to his garden shed – Mission Control – convinced he can launch the rocket by moving the engine. Mary, an old colleague from the now defunct Aber Ivor Carriage Works, offers to help. Special needs teacher Pam, who is concerned about Tom's schoolwork, arrives, unimpressed by George and his mate Barney testing rockets in the back garden.

George unwittingly takes Mary to an expensive Japanese restaurant, while Angela sneaks out to see Ed, a boy she fancies from school, perform with his band. Tom is left alone.

The next day, Pam tells George that Tom has been missing lessons to spend time in Mission Control. The meeting goes badly. George feels he has failed his son and decides to scrap the rocket and devote himself to fatherhood. But can he walk away from his dream?

After Bethan One crashes into the sea, George decides to build a new rocket out of aluminium and starts collecting cans. But his enthusiasm for recycling blinds him to Barney and Diane's desperate bid to start a family – and he ends up in an embarrassing misunderstanding with his own daughter Angela.

George has to be rescued by the RNLI after his rocket crashes into the sea. It's too heavy to fly and George decides the best option is to start all over again. He goes with Barney to try and get some aluminium sheets from Lloyd, who runs a scrap yard. There's only one problem – Lloyd wants £150 and they're both broke.

The Old Carriage Works team are murdered by Angela's school at rugby but as Tom tidies the playing field, George realises he could collect aluminium cans to use for a new rocket. He persuades Pam to let him start a collection at school – in return for helping with a model rocket competition. George is in a buoyant mood after Mary gets him a meeting with a recycling plant, but it's a bad night for his babysitters Barney and wife Diane when they discover she's not pregnant – again. Later, George finds the pregnancy testing kit and thinks it's Angela's.

After an embarrassing chat with his daughter, George confronts Ed. Meanwhile a depressed Barney visits a consultant, missing his appointment at the recycling plant. George is angry and Barney resigns, while Diane is also hiding something. As the misunderstandings multiply, can the friendships and space programme get back on track?

Barney and Diane ask George to be their sperm donor and are thrilled when he appears to accept. But George is worried about finding a new HQ for his rocket after an explosion at Mission Control. They go to the carriage works, but things don't go to plan with either the rocket – or the plans for fatherhood.

In the midst of an explosion at Mission Control, Barney asks George to donate sperm. George is shocked and also threatened with arrest for keeping hazardous chemicals in his shed. Desperate for a child, Barney tells an excited Diane he thinks George will help.

George goes for extra lessons with Tom's teacher Pam in a bid to improve his reading, but his mind's really on finding the right mix of fuel for Bethan Two and a new place to carry out his rocketeering. Along with Barney, Huw, Lloyd and Tom, they head for the Aber Ivor Carriage Works where Shiner is on night security duty. He reluctantly lets them in.

The next day, the men return and break into the welding shed while Tom distracts the day shift guard. Later, George goes to a dinner party with Mary, who is keen to become more than friends. Angela doesn't like it, and her mood isn't helped when Ed cancels their date because the lead singer's walked out of his band.

George gets to the Carriage Works just in time to witness another explosion. In the aftermath, he agrees to donate sperm, soon regretting it when Angela hits the roof. Pam helps George make some important decisions - but when Carriage Works owner Eric Davies eventually lets him have his rocket back, George has to consider how he can track it in space to make sure his wife's ashes go where they are supposed to.

George and his friends build a ramshackle tracking device for the rocket and set about testing it. Things look up for sacked security guard Shiner when he gets a job at the chocolate factory. But trouble starts when union man Huw squares up to his old rival Eric, then Shiner drops the tracker into a vat of caramel.

George and his friends build a tracking device so they can establish when the rocket reaches space. To find out if the ramshackle device will work 62 miles above the earth, Shiner heads off to the coast, but Huw's aerial snaps and the rocketeers lose him after only a mile.

Shiner's wife Fiona is angry because he'd promised to spend the day job-hunting after Eric sacked him from the carriage works. She blames George for their woes so he sweet-talks his Human Resources Officer Gail. She gives a delighted Shiner a job at the chocolate factory in return for George becoming her liaison officer with the staff.

Eric lets the team back in the Old Carriage Works and Angela, now a singer in Ed's band, moves their rehearsals into Mission Control. But it's not long before trouble starts again. Huw, a former shop steward, can't work alongside his former boss Eric, while Shiner accidentally drops the tracker into a vat of caramel.

Gail confronts George after the tracker is found and tells him to sack his mate. Shiner and Fiona have a fight, then the bailiffs appear and he disappears in George's car, saying he will kill himself. The only hope is using the tracker to find him. Can the team forget their differences to save their friend – and will the tracking system work at last?

George is busy preparing to launch the rocket on the anniversary of Bethan's death, when he suddenly has second thoughts. Diane is pregnant and Barney starts celebrating – but is it too soon? As the team face personal setbacks, can they achieve their dream of launching the first Welsh rocket into space?

George is thrilled to get the council's permission to launch Bethan Two on the first anniversary of his wife's death. But fire officer McNulty fails the team on their safety inspection. Without it, they can't launch the rocket.

In the midst of the build up, Diane discovers she is pregnant. Barney is thrilled and starts celebrating immediately, refusing to let anything spoil his elation - even McNulty's impossible demands that they put up safety fences and an observation deck on the beach.

Angela's band is booked for their first gig. She wants George to be there and Tom wants his dad to help at the school food fair. George seems depressed and won't get involved with either of them. Suddenly he's not ready to let Bethan go, especially in front of the whole town.

To the dismay of the team, George announces he is cancelling the launch and goes to find Tom and Angela. Barney appears, tearful after a visit to the hospital with Diane. George realises he must launch the rocket and move on. It is time for the team to gather on the beach to put their rocketeering to the ultimate test – and for George and his children to say goodbye.