The Helliax Rift is out today.

Daniel Hopkins thought he knew what he was letting himself in for when he joined the top-secret UNIT organisation as its latest Medical Officer.

Racing about the countryside, chasing strange lights in the sky? Check. Defending the realm against extraterrestrial incursion? Check. Frequent ear-bashings from UNIT’s UK CO, the famously no-nonsense Lt-Col Lewis Price? Check. Close encounters of the First, Second and even Third kind? Check, check, check.

But he had no idea what alien beings were really like. Until the day of the Fallen Kestrel. Until the day he met the Doctor.

Writer Scott Handcock told us more about this new UNIT trilogy of adventures: “It’s a thrill to write a UNIT adventure for the Fifth Doctor – and stranger still to think he’s never had one before. It’s a fun dynamic to play with and a bonus to establish new characters who will recur across the Main Range. It’s Peter and a brand-new UNIT team, led by Russ Bain as Lieutenant-Colonel Price, with Genevieve Gaunt as Corporal Maxwell and Blake Harrison as UNIT’s new medical officer, Lieutenant Daniel Hopkins.

“Script editor Alan Barnes worked hard to assemble a team that work across the trilogy of adventures, and director Jamie Anderson’s done all the characters justice with some brilliant casting. But it’s safe to say that UNIT and their former scientific adviser don’t exactly see eye to eye…”

You can get The Helliax Rift now at £14.99 on CD or £12.99 on download. All CD purchases unlock a download option via the Big Finish app and the Big Finish website.

Or you can save money by getting a subscription to the Doctor Who Main Range. When you subscribe you'll get 30% off the price, free specially recorded Short Trips stories, PDFs of the scripts, and extended downloadable extras. You can subscribe for either 6 or 12 releases.

Coming next month in the Doctor Who Main Range the Sixth Doctor gets a new companion with Mathew Sharpe in The Lure of the Nomad.

For thousands of years, it has drifted through space, unimpeded, forgotten, seemingly lifeless. Now, finally, it has been discovered.

Responding to a distress call from the mysterious hulk, the Doctor and his companion, space pilot Mathew Sharpe, walk into a desperate situation. The multi-tentacled semibionic Makara were tasked with renovating the abandoned craft, but now they’ve begun murdering their employers.

The Doctor soon realises that the Makara have been programmed to kill, but by whom, and for what reason? Finding out the truth will mean uncovering a secret that threatens the entire universe.