The new radio anthology series Stop Signs created by Anna Mahtani and Rebekah King is a mixed bag. A simple premise – each episode being a play set within a car journey – is both the greatest strength and weakness. While such a blank slate has allowed impressive creativity from a range of actors, directors, composers and writers, the temptation to overstuff results in tonally clashing plots. Nevertheless, it’s worth tuning in to hear what the next stop is.

The plot of the first two episodes goes something like this: Episode One, Ten Thumbs and a Cadillac written by Bill Dallas Lea features a road trip to a Nevada desert complete with sheriffs, aliens and a fairly predictable whodunnit. Episode Two, Carmen Sanchez vs the Universe written by Genevieve Badia-Aylin is about two friends and a mysterious interloper trying to get back to a wedding at the start of a zombie apocalypse.

The first two episodes have a lot in common. Both are apparent comedies, though they’re both more successful with character work than the conceptual. Sometimes the jokes land: “Something ain’t sitting right”; “Ok I won’t cross my legs,” got a laugh in Episode One. More often though they fall flat.

Both feature a number of twists. While the reveal of the first episode is ploddingly obvious, the second’s reveal is so unexpectedly odd that this reviewer burst out laughing. Whether this was the writer’s intention is unknowable, though it speaks to the tonal confusion that characterises the second episode.

“Sometimes the jokes land: “Somethings ain’t sitting right”; “Ok I won’t cross my legs,” got a laugh in Episode One. More often they don’t.”

Both episodes are surreal. The ghost of David Bowie for instance shows up for a dream sequence self-consciously stolen from Flight of the Concords in Carmen Sanchez. However, the fantastical in both episodes struggled to make the impact it felt the writers were reaching for. To suspend the disbelief of the listener the rest of the action/characters need an authenticity that’s too often missing in Stop Signs. Why do they keep driving in the first episode even though someone’s died in the car? Why do they stop for coffee in the second episode even though they’re running away from zombies? It’s hard to get invested in characters you don’t believe in let alone appreciate the weirdness of ghost Bowie.

Given the lack of a visual component, the flawed writing of Stop Signs becomes exaggerated. The first episode’s conversation goes in a circle: each character accusing the other of murder until the obvious twist is resolved. The second avoids this with more external action for the characters to respond to and as such has more momentum for the story. Both episodes often have pointless dialogue: one character will say one thing, the other responds with a few words or a prevarication which shuts down the conversation. Nothing develops out of the exchange of only two lines and story developments thus take place within enclosed snippets of dialogue, with no attachment to what came before or after. For a show based on conversations, they just don’t sound real.

These criticisms are not to belie the creativity of the plot or characters which the writers should get enormous credit for. However, given the radio form, tighter writing would have made for a more striking listening experience. Indeed, had these plays been performed live, it’s likely that the added physicality would have covered some of these issues.

The final episode reviewed avoids these errors and is the best of the three. Burnt Icicles Keeping Warm written by Emma Robinson is a drama taking place after a funeral. A nine-year-old girl Elena and her guardian Dan discuss grief, love and death. The dialogue is tighter, more humanistic and eventually capable of supporting an emotional conclusion. This episode is more tonally confident, comfortable being a quietly tragic drama while also finding humour in that darkness. Having one character as a nine-year-old girl who can sit outside the norms of adult style conversation, making the episode a two hander rather than a variety of characters and focusing on emotions instead of external events, means that Burnt Icicles makes the most of the format in a way the first two were unable to.

“This episode is more tonally confident, comfortable being a quietly tragic drama while also finding humour in that darkness”

In terms of the acting, the cast are generally good. Ryan Morgan was the star of the first two episodes playing Glaswegian Dan, the Sheriff and the ghost of David Bowie. His conviction and solid impression work offered some of the best lines. The star of the third episode, Katy Lawrence offers an interesting contrast but is equally as capable. Lawrence acts with a lighter touch than Morgan but to great effect, particularly in the genuine closing minutes of the last episode.

The production of Stop Signs is its secret weapon. Aside from some looseness in the dialogue, the transitions, sound design and direction are excellent. Each episode is intercut with music which sets the tone and breaks up the dialogue. The directors and composer Angel Wong are able to bring a professional shine to the production: rain on the roof of the car, seatbelts, the thump of the car hitting something …

Stop Signs isn’t perfect. It’s at its funniest, most successfully surreal and genuinely moving in the simple moments. While I’m looking forward to the next episode, let’s hope that there’s a few less passengers.