The Colonel, owner of Follyfoot, the Home of Rest for Horses, has been ill and has to go away to convalesce. Dora and Steve are left in charge, with the strict instruction, 'Don't buy any horses'. But when Dora sees the rangy, cream-coloured lame horse, Amigo, she is determined to save him from spending his last days pulling a heavy log-cart - even if it means borrowing money from sly Ron Stryker. But to pay Ron back, someone from Follyfootmustwin the Moonlight Pony Steeplechase . . .