Bloodhound

You have advantage on survival and perception checks to track or locate creatures that are below their hit point maximum.

Additionally, you can sense the pain of any creature within 30 feet of you that is at or below half its hit point maximum and you know of the exact location of that creature. This spell cannot locate undead, non-living constructs, creatures that do not feel pain, creatures that are protected from mind-reading or divination, and creatures that are sufficiently anesthetized, at the DM's discretion.

The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.