tribute_mission_set_up_tribute_travel_effect

tribute_mission_set_up_tribute_travel_effect = {
	#Recover the tribute_mission_target scope from saved var if it doesn't already exist
	if = {
		limit = { exists = var:tribute_mission_target_scope }
		var:tribute_mission_target_scope = {
			save_scope_as = tribute_mission_target
		}
	}
	else = {
		error_log = "Tribute mission target scope variable not set on character intending to travel!"
	}
	#Travel posted first should look neater in tooltip
	hidden_effect = { # ensure we subtract everything we've offered
		if = {
			limit = { has_variable = offered_gold_value }
			remove_short_term_gold = var:offered_gold_value
		}
		if = {
			limit = { has_variable = offered_herd_value }
			domicile ?= {
				change_herd = { subtract = prev.var:offered_herd_value }
			}
		}	
	}
	trigger_event = { on_action = tribute_mission_start }
	if = {
		limit = { location = scope:tribute_mission_target.capital_province }
		trigger_event = tribute_mission.0002
	}
	#Add the concubine
	else_if = {
		limit = { has_variable = offered_concubine }
		start_travel_plan = {
			destination = scope:tribute_mission_target.capital_province
			companion = var:offered_concubine
			on_travel_planner_cancel_on_action = tribute_mission_travel_planner_exit 
			on_arrival_event = tribute_mission.0002
		}
	}
	#Add the eunuch
	else_if = {
		limit = { has_variable = offered_eunuch }
		start_travel_plan = {
			destination = scope:tribute_mission_target.capital_province
			companion = var:offered_eunuch
			on_travel_planner_cancel_on_action = tribute_mission_travel_planner_exit 
			on_arrival_event = tribute_mission.0002
		}
	}
	else = {
		custom_tooltip = tribute_mission.travel_to.tt
		start_travel_plan = {
			destination = scope:tribute_mission_target.capital_province
			on_travel_planner_cancel_on_action = tribute_mission_travel_planner_exit 
			on_arrival_event = tribute_mission.0002
		}
	}
}

As written in game/common/scripted_effects/tgp_tribute_mission_scripted_effects.txt.