Playbooks

Mtn Spot from the Shotgun Split Slot Offset set is a Spot concept built with a pre-snap motion tag to help identify the coverage shell before the ball is snapped. The near receiver runs a corner route out of the stack, the outside receiver on the strong side pushes vertical up the seam, the tight end runs a quick flat/out to the corner, and the running back releases on a shallow drag underneath from the backfield motion. This is a classic Cover 3 beater built on spacing horizontally and vertically, with the primary read starting on the flat/drag combination underneath before working up to the corner route if the cornerback sinks or the flat defender widens too far.
Pre-snap, watch the safety alignment: if you see two high safeties with a corner playing off, expect Cover 2 or Cover 4 and prioritize the flat and drag combo underneath. If the defense shows single high safety with corners playing outside leverage, that is your Cover 3 shell, take the corner route since the deep third defender will be stressed vertically and horizontally. Post-snap, key the flat defender: if he sinks with the corner route, the drag and shallow options will be wide open underneath for an easy completion. Watch for a lurking linebacker sitting in the middle of the field who can jump the drag route, if he shows early, work the corner or seam instead. Man coverage with no safety help over the top is a green light for the vertical seam route, since the receiver has a clean release against the leverage created by the motion.
Use the pre-snap motion to bait linebackers into showing their hand, either man or zone, before the snap so you can lock in your first read.
Attack Cover 3 shells with the corner route since the deep third defender has to choose between the vertical seam and the breaking route, creating natural leverage.
Hot route the running back into a quicker option route if you are seeing blitz pressure off the edge, since the shallow drag naturally beats man coverage and blitzing linebackers.
Pair this play with Mtn Y Cross or Mtn PA Y Cross in the same set to keep defenders honest on the same route tree while disguising your intentions with similar formation and motion.
Best used on second and medium or third and short since the underneath options provide a reliable checkdown if the deep shots are covered.