Starwars.com has posted the preview version of the episode guide for "Corruption" (S3 Ep. 5) which includes the following synopsis:
"Padm?, on a diplomatic mission to Mandalore, guarantees the pacifist planet the Republic's full protection, but she and Duchess Satine soon find something sinister lurking beneath the planet's serene facade."
Remember, make sure to check out the episode preview and keep your eyes peeled for an update when the full version of the guide goes online.