After Alduin's escape, you need a way to trap a dragon to interrogate it about Alduin's whereabouts. Esbern suggests using the ancient dragon trap in Dragonsreach. This quest involves convincing Jarl Balgruuf to help, which may require you to broker a temporary truce in the Civil War.
Objectives:
- Speak with Paarthurnax.
- Speak with Jarl Balgruuf.
- (Optional) Negotiate a truce at the High Hrothgar peace council.
- Trap Odahviing in Dragonsreach.
Strategy:
Speak with Paarthurnax, then return to Dragonsreach and speak with Jarl Balgruuf. He will be hesitant to help, fearing a dragon attack on his city. If the Civil War is ongoing, he will demand a truce before he commits. This triggers the 'Season Unending' quest, a peace council at High Hrothgar. Successfully negotiating the truce (or completing the Civil War beforehand) will convince Balgruuf. Once he agrees, you'll need to lure a dragon into the trap. Use the Dragonrend Shout on Odahviing, a dragon you've encountered before, to force him to land inside Dragonsreach. Lead him into the trap on the balcony. Once trapped, interrogate him about Alduin's location.