The Nilfgaardian Connection

The Nilfgaard Connection is a main quest of The Witcher 3: Wild Hunt and the first quest following Act I which follows the Prologue.

Quest Description
"Geralt traveled to Velen in search of Ciri, an act that attested to the depth of his devotion. Only a man who has been to this land can know just how vile it is. At this time it was commonly known as No Man's Land.  Why?  Well, the emperor of Nilfgaard had not yet claimed it, Temeria was in disarray, and the Redanians had already retreated north.  No Man had been left in charge, and he had proved a terrible ruler. Geralt needed to find Hendrik, an imperial agent who had been working on Ciri's case, and to collect from him what information he had managed to gather."

- Dandelion

Travel to Velen
After collecting your things walk to the front door of the palace in Vizima in order to fast travel to Velen at the Hanged Man's Tree. You may want to stop and play gwent with one of the noblemen in the gardens before leaving the palace if you think your deck is strong enough. He may not be in the palace later on so it might be worth a try to get his gwent card now.

Go to the Inn at the Crossroads
As you ride up to the Hanged Man's Tree you'll again take control of Geralt. Several quests will have been initiated in you journal including: In Ciri's Footsteps, Pyres of Novigrad, and Destination: Skellige. These are the quests which will see you through your search for Ciri as part of Act I. Don't worry about all that now though, just proceed through the sad village of Mulbrydale and across the river to the Inn marked by the objective marker.

Ask about Hendrick
When you enter the Inn you can either go straight into conversation with the Innkeeper to progress the quest or speak with the couple at a table nearby to learn a tidbit about the current ruler of this land you've arrived in. The innkeeper isn't too forthcoming with information about Hendrick. As soon as you sit down to enjoy a drink the inn clears out and a group of the Baron's thugs enter. You can choose any of the following three options with the associated result:

Defeat the Baron's men (optional)
''Note: Your actions with the baron's men here will affect how easy it is to gain entry to the Baron's fort at Crow's Perch during the main quest, Bloody Baron. None of your actions will make things impossible later on, but the nicer you are the easier it will be to gain access to the fort.''
 * 1) Back off or die: Causes the baron's men to become hostile and you will be given the objective to defeat the baron's men.  Additionally, more thugs will await you outside the Inn which you can avoid if you sneak out the back door should you choose to.  The innkeeper will be upset that you have caused trouble and possibly brought the baron's attention to their village but he will tell you what you need to know about how to find Hendrik.  Afterwards you may either sneak out the back door to avoid more confrontation with the baron's men or go ahead and kill them all.
 * 2) I'm a witcher: Causes the baron's men to fear you and they will leave you alone to finish your drink.  The innkeeper will thank you for not starting trouble with the baron's men and give you the information you need to find Hendrik.  Afterwards you can continue to question the innkeeper to learn some more tales about the bloody baron.
 * 3) Care for a drink?:  This will lead to a second choice and third choice where you can choose to either pick a fight with the same result as option 1 or calm them down leading to the same result as option 2.  If you do buy them a drink you won't actually pay any but you can glean some details about this land's current ruler, the bloody baron.

Look for Hendrik in Heatherton
Not far away from the inn is a town called Heatherton where Hendrick was living, which has recently been raided by the Wild Hunt. After fending off some rabid dogs attacking a man Geralt listens to his story and learns that the hunt destroyed the village, but singled out Hendrick and tortured and interrogated the information concerning Ciri out of him before killing him. Searching Hendricks body inside of the nearby shack Geralt searches his boot and finds a key to the cellar.

Going into the cellar after using the Aard sign to blow a rug off of it Geralt reads Hendricks notes and learns of two possible sources of infomation concerning Ciri, the Bloody Baron and a Swamp witch.

Trivia

 * Missingposter.png the wooden gate into the village at the crossroads there is a missing poster for Tamara Strenger, Philip Strenger's (the baron) daughter. It offers a hearty reward to any who can rescue her from what is presumed to be a kidnapping.
 * As you approach the Inn at the Crossroads you can hear the conversations from several villagers seeming to prepare for an approaching group of thugs. One involves the slaughter of a pig to keep it out of the hands of thieves and the other is a villager that tells his daughter to flee to the woods.