Spy Discovered
The Chase sequence
At any turn during or at the conclusion of the mission, whether succeeded or failed, your Spy may be discovered by the police of the target civilization. When your spy is discovered, the target civilization's leader will demand you cease spying on them. The leader will also gain a Casus Belli against you.
Furthermore, if a Spy is discovered, he or she will need to escape from the target city. You will be prompted to select the mode of escape. There are four possible options:
Airplane (requires an Aerodrome District in this city) - The Spy attempts to fly away. Very dangerous, because the police always watch airports! But they will take only 1 turn to arrive in HQ.
Boat (requires a Harbor District in this city) - The Spy attempts to escape by a vessel. Quite dangerous, since the enemy police always watch seaports too. They will return in 2 turns.
Vehicle (requires a Commercial Hub District in this city) - The Spy attempts to escape by a land vehicle. Somewhat dangerous, but the police usually have trouble watching all roads leading out of the city. They will return in 3 turns.
Foot (always available) - The Spy attempts to flee on foot. Not very dangerous. Think of it, who can surround the entire city with agents? They will, however, return in 4 turns.
If your spy fails the escape, they may be captured or killed. The faster the escape mode, the less likely your spy can escape successfully. The dice roll occurs within the turn. That is, actions during the current turn can affect the outcome of the roll.
If the Spy manages to escape, they will appear in your Capital6 Capital after the respective number of turns, ready for a new assignment. Even if the mission is interrupted, a successful escape may still bring back the loot or a successful pillage report.
Spies may also fail to accomplish a mission without being discovered. In this case you won't gain anything, but the Spy may continue working normally.