Manhattan fireman Mark Decker visits, for the first time, his Steven in his ex Emma's new apartment in one of her dad Donald Richardson's development estates, at the foot of Diamand-back Mountain. But Don's ambitious executive Stewart Hancock, who dreams of his own firm, has been cutting too many corners, at the expense of safety, causing a landslide. Mark gets trapped with Steven and the new concierge Harold, who knows everything about an additional danger: rattlesnakes awoken early from hibernation. Now Mark discovers artistic, nerdy Steven only did 'manly' stuff in the city because dad-son time is so rare. While they soldier on, landscape architect Emma discovers the truth and counters Stewart's plan B to literally cover it up.