Lie to Me is in Mexico this week and while there, Lightman and Emily work on a case involving a missing American woman Marla who has been missing for 2 days. She has a daughter that is in Mexico too. Lightman invites Torres in on the "fun" as well. Meanwhile, back in the United States, Foster looks into tainted blood in D.C. hospitals and needs to go through different people who could have tainted the blood. Getting down to the final details in both cases proves a little bit of cat and mouse but in the end everything works out for the best. Lightman plays a little bit protective of Emily throughout their trip and in the end both take a little to enjoy their well deserved vacation.