return_guardian_travel_effect

return_guardian_travel_effect = {
	if = {
		limit = {
			is_foreign_court_guest = yes
			NOR = {
				host = liege
				is_playable_character = yes
				any_relation = { #They're not at another ward's court
					type = ward
					is_playable_character = yes
					this = $GUARDIAN$.host
				}
			}
		}
		show_as_tooltip = { return_to_court = yes }
		location ?= { save_scope_as = starting_location }
		set_variable = {
			name = ward_educated
			value = $WARD$
			years = 3
		}
		set_variable = {
			name = ward_educated_realm
			value = host.primary_title
			years = 3
		}
		# Actually return guardian last
		hidden_effect = {
			set_location = scope:starting_location
			start_travel_plan = {
				destination = liege.capital_province
				on_start_on_action = on_guardian_depart_for_home
				on_travel_planner_cancel_on_action = on_guardian_depart_travel_planner_exit
				on_arrival_on_action = on_guardian_arrive_at_home
				on_arrival_destinations = last
				return_trip = no # One way
			}
		}
	}
}

As written in game/common/scripted_effects/00_education_effects.txt.