"The Debt," a solid political thriller, is best seen with only the vaguest understanding of the plot.

"The Debt," a solid political thriller, is best seen with only the vaguest understanding of the plot. What was evident from the fine trailer, that disclosed little, was the presence of a top-drawer cast that includes Helen Mirren and Jessica Chastain, both portraying Rachel Singer, a Mossad agent — Chastain in 1965, on assignment in East Berlin, and Mirren some 30 years later, now retired and living in Tel Aviv.

The East Berlin assignment anchors the film and opens with young Rachel joining two other agents, Stephan (Martin Csokas) and David (Sam Worthington). Their mission is to kidnap Dr. Dieter Vogel (Jesper Christensen), a World War II war criminal, also known as the surgeon of Birkenau, a Mengele psychopath who performed tortuous experiments on women in the death camp.

When Vogel is captured, they will escape to the West, then to Israel, where the doctor will stand trial for crimes against humanity.

The trio is ensconced in a seedy Berlin apartment, much like the city, monochromatic and depressing. Rachel and David pretend to be a young married couple, desperate to have children.

When they finally receive word that Vogel's identity has been confirmed, the riskiest part of the assignment then is set in motion.

The success or failure of the kidnapping initially rests with Rachel. It is she who must visit Vogel, who runs a fertility clinic, and submit to two harrowing pelvic exams. Each visit is fraught with a palpable tension as the doctor makes inane small talk, quizzing Rachel about her family's fertility history. She must convincingly portray a young woman from Argentina who is having trouble conceiving. Throughout both exams she looks at Vogel, steeling herself to smile, aware that she is in the presence of evil, a monster. Yet she must willingly submit to him as he performs his intrusive exams.

What occurs at the end of her second visit frames the film, in real time and in 1965. It alters their lives forever.

When they return to Israel, they are greeted as heroes. And yet there is a reservation and hesitancy that defines them, now 30 years later. They are haunted by events and remain unable to fully embrace the adulation bestowed on them.

We see Tom Wilkinson as Stephan and Claran Hinds as David, now middle-aged men who look at each other as if their memories belie the publicly proffered tale of courage offered up and reinforced over three decades.

What lies behind their remoteness, their ability to only find the barest joy in their celebrity status, is central to the film and must be seen fresh, without even a hint of the cause or the outcome.

"The Debt" is a finely crafted film and a late-summer surprise, and a wonderful segue to the fall movie schedule.