Northwest Territory

When old Fort MacKenzie prospector Kellogg returns to his cabin one day, two robbers knock him out and ransack the cabin for a map to a secret claim that Kellogg alluded to earlier at the fort trading post. Kellogg comes to just in time to take a shot at the men who flee before finding the map, setting fire to the cabin in their haste. Canadian Northwest Mounted Policeman Rod Webb is traveling by canoe with Kellogg's recently orphaned grandson Billy, when they hear a shot and rush to the cabin. Rod pulls Kellogg from the flames but the old man dies in Rod's arms before he can reveal the secret claim to his grandson. Meanwhile, Rod's clever dog Chinook catches the scent of the murderers, chases them through the woods and attacks one of them, ripping some material from the robber's mackinaw coat. Rod returns with Billy to Fort MacKenzie and asks his old friend and trading post clerk Ann DuMere for assistance in solving the case and for her to keep Rod's identity a secret. Ann remembers that Kellogg mentioned a claim map and that mail arrived for Kellogg after he left the post. That night, Rod and Ann sneak into the mailroom to check for the letter hoping that it might give them a clue, but it is missing. The next day, when Rod and Chinook return to the burnt cabin, Rod spots a bell jar containing the map in the rubble. A stranger lurking in the hills sees Rod, shoots and wounds him, then disappears into the woods. While Ann dresses Rod's wounds back at her cabin, Rod explains that he found shards of preserve jars in Kellogg's cabin and Ann remembers that Kellogg bought the jars several months ago. Later trading post owner Dan Morgan introduces Rod, posing as a novice prospector, to visiting mineralogist Kincaid. Kellogg had asked Kincaid to investigate the claim and Kincaid now promises he will gladly give Billy his rightful share once the claim is found. Outside the trading post, Chinook recognizes a local, LeBeau, as one of the murderers and barks viciously. LeBeau pulls out a gun to shoot the dog, but Rod, having heard Chinook, wrestles LeBeau for the weapon. After townsmen pull the men apart, Morgan orders the dog killed, but relents after Rod promises to keep a watchful eye on him. Later, Billy and Chinook secretly track LeBeau to a cabin on the edge of the settlement, where Billy hears LeBeau and another man plot an ambush. Billy reports back to Ann, who knows the cabin belongs to local ruffian Dawson. Ann then sends Billy to Kellogg's cabin to warn Rod, but when they encounter Dawson on the trail, the dog attacks and pushes him off a rocky precipice to his death. Meanwhile, Rod has surmised from the map that the claim is somewhere near an old rock formation called the "Old Indian." Following arrows left by Kellogg on the rock, Rod finds the pool of crude oil. Meanwhile at Ann's cabin, townspeople gather and demand Chinook be handed over because he killed Dawson. Billy, desperate to save Chinook, reveals to Morgan and Kincaid that he overheard LeBeau and Dawson talking about killing his grandfather. Morgan is forced to postpone judgement about killing Chinook until Billy's accusation can be investigated. Under cover of darkness, LeBeau visits Morgan with whom he is secretly in league. When Morgan tells him of Dawson's death, they decide they must kill Rod to keep the claim a secret. Early the next morning Billy ties up Chinook deep in the woods to protect him from the townspeople. LeBeau and Morgan, who have followed them, kidnap Billy and lock him in Dawson's cabin. Soon after, LeBeau spots Rod on the river in a canoe and shoots, and Rod falls from the boat. LeBeau assumes Rod is dead, but Rod safely swims under the dock, well hidden from the murderer. Meanwhile, Chinook breaks free from his leash, finds Ann and leads her to Dawson's cabin, but before she can free Billy, LeBeau captures her. When LeBeau opens the door to kill Chinook, Rod, hidden behind the door, knocks the gun from his hand. Chinook then attacks and kills LeBeau while Rod subdues Morgan. Kincaid arrives and holds them all at gunpoint, but Ann knocks him out with a log. With the mystery resolved, Rod takes Morgan and Kincaid to the proper authorities, leaving Ann to care for Billy, whose rights to over a half of a million dollars in oil have been restored.