'Theatre is dying' is the challenging opening gambit of Graeme Eatough's How to Act. At least, those are the words of Anthony Nicholl (Robert Goodale), who bemoans the loss of something real in modern entertainment that now serves only as escapism and contains no truth.

This search for authenticity permeates How to Act from the off. Nicholl is an acclaimed director leading a workshop with Promise (Jade Ogugua), a Nigerian-born, London-based actress. His exercises challenge her to dig deeper and deeper into her childhood and the country she grew up in. Both actors are fantastic, and their continually shifting dynamic makes How to Act a compelling watch; Goodale's self-important air plays well with Promise's innocence and vulnerability, and later her fury as the tables are turned through a series of flashbacks.

How to Act explores the history of oil production in Nigeria, and all of the corruption and conflict that those riches brought to the country's people, taking that story of exploitation and giving it a new personal and cultural context. It's a production that offers more questions than answers, but the journey of How to Act is powerful, uncomfortable and provocative, reminding us what theatre can do, and the importance of acting and storytelling. Long live the form.

Summerhall, until 27 Aug, 1.15pm, £15 (£13).