Clark needed that time with Merlin to clear his head. It's always best not to take for oneself before speaking and saying something you regret later, because you had spoken in haste and in anger.
Hmmmm. Who was the lone rider? Was he really associated with Luthor? Or was a scout for Tempos in disguise? It's a more horrific situation if the lord under which the Kent family had their home (and protection) was actually in league with the men who burned the farm and killed Jonathan. Perhaps that was the true reason that Luthor sold Clark as a slave, so he wouldn't be in the neighborhood to notice that his animals hadn't actually left the county.
How frustrating it must be for Clark to not only have Lois engaged to marry Luthor, but having to convince her that Luthor is a dangerous fellow. Scary stuff that happened with Arianna.
What will Clark learn at Luthor's stables when he delivers the two horses? Will anyone from Luthor's staff recognize him as a local farmer, whom Luthor sold as a slave? If so, how will he be punished? As I could not see them allowing him to return to the household of the Luthor's beloved (or fiancee as this case more accurately would be) should he be found out, especially if he learns more that ties Luthor to Tempos.
