Several details featured in the sixth episode of "Game of Thrones" season 7, titled "Beyond the Wall," suggest that the great battle of the Frozen Lake was all a trap orchestrated by the Night's King to capture one of Daenerys' dragons.
7. A White Walker patrol? What a coincidence!
A White Walker patrol was an opportunity too good to be neglected. Tormund and Jon decided to attack in less than ten seconds.
6. Only one wight survived
When Jon Snow kills the White Walker with Longclaw, every wight except one immediately dies. How convenient for team Jon!
A lonely wight was exactly what the crew was looking for.
5. Jon's men were forced towards the lake
Now things get serious. After being attacked by a bear who targeted Thoros the Red Priest (exactly the target the Night's King would have chosen), the group notices that hundreds of wights are approaching. Gendry runs towards the Wall, and no one attacks him (it's crucial that he reaches the Wall to send a raven to Daenerys). Where is the group forced to retreat? Towards a frozen lake where Jon and his companions are safely trapped with a wight in good condition. The perfect setup to convince Daenerys to fly north with her dragons.
4. Three javelins for three dragons
When we see the Night's King for the first time during episode 6, he is with four White Walkers.
Three of them are holding ice javelins: three javelins for three dragons.
3. The Night's King could have easily killed Jon
Why didn't the Night's King order his wights to attack and kill the humans as soon as the lake was frozen again? Why didn't he kill Jon with a javelin or using his magical powers? The White Walkers waited for many hours, for more than a day according to some fans' calculations.
Why? Because Jon wasn't the Night's King's target. He needed him alive to lure Daenerys up there.
2. Those giant chains
Not only did the Night's King show up with some ice javelins, he also killed Viserion near a lake where big chains could be found. Looks like he thought of everything.
1. How the Night's King orchestrated the trap
Our theory is simple: he's a greenseer. That's how he organized everything. We know he can use magical powers and we know he's been created by The Children of the Forest. We also know that he can sense when Bran is using his warging and time-traveling powers. We don't believe the Bran-is-the-Night's-King theory, but we think it's totally plausible for the Night's King to be a greenseer.