On September 26, Price began moving his army from Fredericktown towards the Arcadia Valley, with Fagan's division in the lead. The entrance to the valley, Shut-In Gap, was unguarded, so Fagan sent Colonel William F. Slemons's brigade, temporarily under the command of Colonel John C. Wright, forward. Wright, with about 250 men, surprised a small Union detachment, which managed to send a messenger warning a detachment of the 47th Missouri Infantry Regiment at Ironton and the Union command at Fort Davidson, further north. Ewing responded by sending 80 men from the 3rd MSM Cavalry Regiment to investigate the reports. Wright's men scattered the MSM soldiers, but were repulsed by the detachment of the 47th Missouri Infantry when they tried to drive through Ironton. After hearing the sounds of battle from the valley, Ewing sent Major James Wilson and several hundred cavalrymen towards the fighting and later followed Wilson himself with a force from the 14th Iowa Infantry Regiment and two cannons from the 2nd Missouri Light Artillery Regiment. The two groups joined with the Union detachment already in Ironton around 15:00, attacked under the command of Wilson, and drove Wright back towards the gap. Ewing, under the impression that he was fighting with Shelby's men, left Wilson and his force in the valley and personally returned to Fort Davidson. He then made preparations to defend the fort against Confederate attack and send extra supplies up the railroad to Smith.