Jess is thrown by Joan's reaction when she outs Melanie's cheating in Friday's Fair City on RTÉ One and the RTÉ Player.
Melanie cheated in her exams to get top marks - and Jess has turned detective.
"I put the pieces together," Jess tells Joan. "I just... I can't prove it yet."
"If you're going to make an accusation like that, you better have undeniable proof," warns Joan.
Watch what happens next on Friday on RTÉ One and the RTÉ Player at 7:30pm.
NB: There is no Fair City episode on Thursday due to the second Eurovision Song Contest semi-final.
