"The Lies We Tell" is the 30th episode of the 28th series of Casualty. It was preceded by "Gravity" and followed by "Valves to Vagrants". This episode features the temporary departure of student paramedic Iain Dean, who later returned that October.
A group of activists set a trap in a road as they hope to wreck the tyres of passing motorists, but their efforts go horribly wrong when a lorry crashes. One of the group races to help the driver but ends up being injured himself. Later at the ED, Ethan's conscience is tested when the activist asks him to hide his secrets…
Meanwhile, Rita and Zoe help a desperate prisoner repair his relationship with his mother.
Elsewhere, Lily goes head-to-head with Ash as she continues to pursue her complaint against him.