Typically in strategy games you are given or have to build a base, so that you can have an endless supply of units as long as you have access to resources, and you can rebuild destroyed buildings.
However, in this mission (it is usually a campaign mission) you don't get such a luxury.
You get a handful of units, and you must accomplish your goals without losing all of them.
A Baseless Mission
typically includes most of these restrictions:
- The premise is that you are behind the enemy lines, fleeing from somebody, or exploring a new territory.
- At least one of your soldiers is a hero unit, if the game includes them.
- You lose the mission if you lose your whole army or - usually - the hero.
- Reinforcements are acquired at certain milestones during the mission, be they found, rescued or hired.
- You may get the base back halfway through the mission, have extremely limited resources to work with, or have the ability to capture parts of the enemy's base.
- These missions typically become That One Level if the game is not suited for tactical combat well or the amount of units given isn't enough to deal with enemies.
- Warcraft: Orcs and Humans has several campaign missions like this.
- Warcraft II: There are a total of six such missions in the vanilla game and its expansion.
- In mission 6 of the Orc campaign, you escort a moderately-sized band of orcs and trolls led by Cho'gall to a certain location.
- In mission 9 of the Human campaign, you receive a full army and navy in order to escort Uther Lightbringer across the map.
- In the expansion, the first mission of each campaign gives you no peasants (although you do have access to a handful of buildings and the upgrades that can be purchased from them).
- The seventh human mission in the expansion does give you peasants, but they can't build any military structures; and the ninth orc mission again has no peons, only a few buildings scattered across the map and a finite amount of resources to buy the upgrades from them.
- Frequent in Warcraft III, where you usually get to play as a main hero of the current campaign plus a handful of units.
- In Frozen Throne, the whole Orc campaign is RPG-style.
- Starcraft: Each campaign in both the vanilla game and the expansion pack has several missions like this. They typically require careful micro-management as there is no easy way to heal your units. These missions are often referred to as "installation missions" as they usually take place on maps made from the Installation tileset. Tangentially, said tileset has no tiles which allow placement of buildings.
- Starcraft II: The baseless missions in Wings of Liberty, the first game in the Starcraft II trilogy, are considerably less frustrating than its predecessor's, and only one (the first mission) is mandatory for a given playthrough, although there are six in total. Most normal missions are tailor-built for showing off a new unit, and disallowing production of a new toy is likely not considered a sound design choice.
- A staple trope of Command & Conquer series, encountered at least once in each installment. Each hero got at least one mission dedicated to him or her. Often doubles as Stealth-Based Mission.
- Any of these missions from Tiberian Dawn apparently expected you to literally take on a base by yourself, making them quite Nintendo Hard. Later literations would always add some sort of script or conveniently placed barrels to help you through the level.
- You get to play as the main character exclusively in Impossible Creatures' campaign.
- Empire Earth did that with Middle Ages campaign.
- Age of Mythology did that a handful of times.
- Age of Empires II has at least one in every vanilla campaign, often as the first mission. You start Joan of Arc with just Joan and a ragtag band of supporters, and while your army increases, you never get to build a base. The second-to-last mission in the same campaign has you take Paris with a sizeable but non-replenishable army. The first Mongol mission is particularly developed, as you need to perform sidequests for the various tribes around the map to earn their allegiance as well as reinforcements.
- Warzone 2100 had two types of missions in its campaign mode: One involved searching the map, collecting your usual resources and expanding your base while fighting off enemy units and completing mission objectives. The other were "transport" missions where you loaded an air transport with a set number of units to accomplish mission objectives on a completely different map. You were, however, generally allowed to review your base's production/research schedules and arrange reinforcements from home base.
- Metal Fatigue had a level where you only had one combot and no base and had to heal it by scavenging spare parts.
- Heroes of Might and Magic IV introduced these into its series in some campaign missions where you were just given a hero or several and no towns, and HOMM V followed suit. In previous games, you always lost the game in a week after all your towns were captured.
- Several missions in State of War let you start with a handful of units and nothing else. Some of them let you capture enemy factories and win as usual, other (like escort missions) don't give you that luxury.
- Inversion: mission in Greece gives you a base but no means of acquiring unit factories - you have to win by building lots and lots of towers.
- World in Conflict doesn't have a base per se (only stationary drop zones) but most campaign missions restrict your ability to call in reinforcements at some point. There are two missions in the vanilla game where this is played straight, however:
- In the first American mission you use a handful of squads to fight the invasion in Seattle. About halfway through you get access to the National Guard depot, however, which gives you an APC that gets replaced for free if it's destroyed.
- In the eleventh American mission you start with only repair tanks, and have to let your AI escort do most of the fighting until you can salvage some vehicles. While technically an Escort Mission, the emphasis is on deft micro-management and clever use of support abilities.
- The fourth Imperial guard mission in Warhammer 40,000: Dawn of War: Winter Assault is a baseless Escort Mission. The Land Raider you are escorting is exceptionally tough, the incredibly numerous enemies are very weak and the Space Marines get constant reinforcements. You can call in reinforcements yourself at certain points during the mission, but there are enough enemies that the production buildings get cut off when you move past them.
- One mission in Dark Crusade is especially hard because of this. Ironically, completing it unlocks the ability to deploy a forward base when attacking other territories.
- Strangely, the one mission where being baseless would make sense (as it happens underground), it's a stronghold mission.
- Dawn of War II however is (almost) entirely baseless. The single player campaign (up to the Retribution Expansion Pack) consists only of reinforcement points to rally around to bring depleted squads back up to full strength. The multiplayer mode has slightly more in the way of bases, in that each player has a single building as their main base, and can fortify other specific strong points, but these are pretty far removed from traditional base building.
- Company of Heroes has a few. Mostly involving paratroopers, who have the ability to reinforce their squads anywhere, and could drop new squads with a support power. Since resources were gained by territory control, it was still possible to have income without a base.