Out of the Fire

Out of the Fire is a quest in Fallout 4.

Detailed walkthrough
Once the quest is active go to Finch Farm on the upper east coast. Speak with Abraham Finch and he'll tell you that his son ran away to join The Forged raiders in the nearby ironworks. His son stole his sword when he left, Abraham wants the sword back, but couldn't care less about his son. You still get an optional objective to return his son.

The ironworks entrance is guarded by a group of Forged, they are fairly tough as far as raiders go, so caution is advised, but they should be beatable. Once inside there are more Forged patrolling. The entry is on the west side of the building, the goal on the east. There's two ways to get across, an Advanced locked door in the middle level, or a walkway across the top.

The goal is the northwest corner of the east side, there's a turret guarding the exit to the blast furnace. Once the turret is dealt with move on. Opposite the exit to the blast furnace is an exit to the roof, but there's nothing up there of consequence, just more raiders.

On entering the blast furnace the player will immediately be caught in a conversation. Seems that Slag isn't too impressed with Jake and Jake isn't in a great situation at the moment. If Jake is told the truth, that his father only wants the sword, then he'll perform the test and everyone will turn hostile. He can be encourage to perform the test, but that also results in everyone turning hostile. Sarcasm, convincing Jake that his father wants him back, or a straight up moderate difficulty persuasion check can make Jake fight on the player's side.

The fight will be difficult either way, Slag is powerful and equipped with power armor and has 3 allies. There is a lag time between the end of conversation and the start of the fight though, so using VATS to queue up multiple strikes before the fight officially begins can even the odds considerably.

You can also attempt to pickpocket the fusion battery from Slag's Power Armor before the fight. This will make Slag much easier to defeat, and you can use the armor against him. However, this will make the Power Armor counts as a stolen item.

Option 1: Save Jake
Once the fight is over Jake will ask you to meet his father with him, grab the sword from Slag and meet him at the designated spot. The reunion isn't exactly happy, but with some pressure from Jake's mother things go all right. Jake will also join the settlement. The sword does not need to be returned. Abraham may allow you to keep the sword, telling you that it could do some good.

Option 2: Kill Jake
If you kill Jake, you simply return the sword to his father. You have the option to inform his father of Jake's death, to which he will reply a bit dismayed though not surprised. He then allows you keep the sword.