Fall of Lordaeron

Marwynn's Betrayal
When Prince Arthas returned to Lordaeron and brought it to destruction, Marwynn revealed his treachery to the family. He was a student under Kel'Thuzad, a member of the Cult of the Damned, and help spread the plague in Lordaeron. After his confession he lashed out at his family with his Shadow Magic, killing his eldest siblings, Derek and Sarah, and his mother. His other siblings present at the time; Falric, Trace, and Lucas, revolted against their corrupted brother. Marwynn was too confident in his powers, thinking he was able to take on all his family at once. Ultimately, Marwynn was over powered and had to flee by means of teleportation.

Exodus to Stormwind
With Lordaeron overrun by the Scourge the surviving family retreated to Stormwind. (Besides for Lucas who remained in Lordaeron believing it had a fighting chance.) The Valonforth Family still felt obligated to their Kingdom, therefore they helped scores of Lordaeron survivors south. Eventually making it to Hillsbrad the mass of people voyaged the rest of the Journey South. They landed in Menethil, where they made their way to Ironforge than from the Deeprun Tram to Stormwind. All the Survivors the Valonforth Family escorted to safety are forever in debt to them.