The exact story prerequisite before Karel's Mothership opens.
S04 EP01 becomes available after every main quest from Pre-Season through S03 EP04 is complete. Skipping an earlier episode blocks the Season 4 line even if the account's power is high enough for later content.
Required sequence
- Complete the Pre-Season main quests.
- Continue through every Season 1 and Season 2 main quest.
- Complete all Season 3 episodes through S03 EP04.
- Accept and complete the S04 EP01 main quest chain.
- Finish And, Tomorrow to meet the stated Normal-difficulty entry condition for Karel's Mothership.
Official S04 EP01 rewards
Completing the episode grants:
- a special chest attachment;
- an Ultimate Alignment Device.
Those are episode-completion rewards. Karel's Mothership, Raven research, Trials, and the Conquest event have separate unlocks and reward tables.
If S04 EP01 does not appear
- check the quest log for an incomplete main quest rather than only the latest episode;
- verify the game has updated and reconnect;
- inspect whether a previous seasonal line has a final conversation or hand-in pending;
- do not confuse the Trials background sub-quest with the Season 4 main line.
Update 1.4.0 also changed the opening Esiemo exclusive quest: A Mission for Esiemo now starts by checking the Unofficial Operation Records Terminal instead of talking to Enzo. That is unrelated to the S04 EP01 prerequisite but can explain an old quest guide mismatch.
What completion does and does not unlock
Finishing S04 EP01 establishes the story side of the Season 4 progression and grants the two listed episode rewards. It does not automatically research Raven, satisfy a public Hard-mode Arche Activity gate, or complete the first Normal Karel's Mothership clear. Treat those as separate contracts after the episode is complete. If an older article directs you to an NPC or terminal that no longer matches the live quest, compare its stated patch with 1.4.0 before changing account or matchmaking settings.
Sources
QUICK ANSWERS
Questions players ask next
What must I finish before The First Descendant Season 4 Episode 1?
Complete the main story from Pre-Season through Season 3 Episode 4 before starting the Season 4 Episode 1 chain.
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Send the exact game problem, platform, and version. Corrections are reviewed before expansion requests.