When Emmi (Fox) mistakenly sends an email to Leo (Tennant), romance quickly blossoms, and the two begin a shared secret life far removed from their day-to-day existences.
The problem is, Emmi is married – but does a virtual affair count as cheating? To what extent does the relationship rely on fantasy? And is it even possible to fall in love with someone you’ve never met?
Tennant fans will no doubt be answering "yes" to that last question as they make a date with David...
Afternoon Drama: Love Virtually, by Austrian novelist Daniel Glattauer, airs at 2:15pm on Thursday 8 March on BBC Radio 4.