For the first ten minutes or so in each of the three new weekly I Am mini-dramas, everything seems to be perfectly fine. Victoria (Suranne Jones), Danielle (Letitia Wright) and Maria (Lesley Manville) appear to have regular lives with loving people around them and within surroundings that make them content.

Victoria has an amazingly stylish home (presumably the fruits of her profession as a property developer), two fun-loving kids and an attentive husband (Ashley Walters' Chris). Danielle is a successful fashion photographer with an open heart and a wise best mate (Sophia Brown's Tara). And Maria has a loving family around to celebrate her birthday. But soon, the cracks start to show and raw emotions rise to the surface, whether it's residual grief, an inability to fully trust or feelings of decades-long regret.

Above all, this second series of standalone stories created by Dominic Savage and written in collaboration with the three lead performers are masterclasses in acting, aided by excellent scripts and vibrant but not unobtrusive direction. The opening instalment in particular has Suranne Jones in startling form, as she veers from being a busy professional whose anxiety is kept mainly under wraps but which seeps out in subtle and unexpected ways. Her gradual deterioration could have been fumbled in many other actors' hands, but here she is imperious, her highly expressive face doing a lot of amazing work. When we discover the reveal behind her mental-health issues, you wonder how she managed to keep it together for so long.

Letitia Wright and Lesley Manville, too, are expert in holding things in for a while, their naturalistic performances merely lending weight to the eruption of emotions when they confront the fault lines within their lives. These almost perfect dramas are only spoiled by that most heinous of TV errors: the over-exuberant soundtrack. Here it comes in the form of a plaintive string and piano melody that reprises across each episode, and which aims to provide a backdrop but instead overwhelms the action and pummels its audience into feeling 'something'. A shame really given that the wonderful work which Savage and his stars put in could easily have stood on its own two feet.

Channel 4, Thursday 5 August, 9pm.