Monsters march in from the right. If they reach the wall they batter it; if the wall falls, the wave is lost (you keep the gold you earned and can try again, stronger).

Place your party. Tap a card at the bottom, then a glowing square: on a tower platform (safe from melee) or in the bailey field in front of the wall. On desktop you can also drag a card onto the field. Cards recharge after use during a wave.

Gold comes from kills, alchemists, the treasury and the falling embers: tap them. Tap glowing orbs to stash powerups on the right, then tap one to use it.

Tap a party member to level it up (perks at 3, 6 and 10) or sell it. Tap the castle (or Keep) to build towers, raise walls, widen the bailey, and buy the Forge, Treasury, Keepfire Beacon and Spiked Ramparts.

The Keepfire charges as monsters fall: tap the flame, then a lane, to burn the whole lane.

Relics: pick one after every wave (you can hold eight). Rekindle from wave 15 on: start over for Embers that buy permanent upgrades.

Keys: 1–0 cards · QWER powerups · F Keepfire · K Keep · Space start wave / pause · S speed · Esc cancel · M mute