Unlocking every achievement in Servant of the Lake on PC requires careful timing during specific chapters, as several secret interactions are easily missed. Below are the working steps to complete missable tasks, handle secret puzzles, and find Kate's brother.

Day 1 Morning Achievements

  1. Petting the Horse: In The Arrival chapter, click on the horse head a few times until it dips after feeding it the carrot.
  2. Feeding the Cat: In Preparing Breakfast, get the milk from the crate, click the cat on the armchair until it licks its paw, and use the milk on it before picking up the dead mouse.
  3. Exercising with Mr. Aldous: In Waking Up Aldous, click on Aldous randomly until he gets stuck, then click him again to unstick him.

Day 1 Afternoon Achievements

  1. Small Repairs: In Preparing the Reception with the duster, dust the picture frame in the Servant's Room until it falls, breaks, and you piece it back together.
  2. Ruining the Bouquet: In Welcoming the Guests, feed the bouquet to the goat before you milk it so it doesn't leave. Alexandra will later note it smells like a goat.

Day 1 Evening and Night Achievements

  1. Serving Matcha Latte: In Serving Tea, get tea leaves from the Servant's Room lockbox and feed the tea to the cat. Take the sticky green substance from the crate after the cat throws up, add it to the tea, and serve it to Alexandra.
  2. Soothing the Baby: In Opening the Reunion, use the retrieved wine from the box on the baby.
  3. Checking for Intruders: During The Night Watch, check the door leading to the garden on your hallway patrols to spot a masked figure.
  4. Chase away the Crow: In Searching the Attic, click the window to make a black bird appear, then scare it away.

Day 2 Achievements

  1. Serving Mr. Aldous his Favorite Coffee: In Preparing Coffee, place the coffee beans on top of the stove in the Servant's Room to roast them before grinding them.
  2. Tickling Mr. William: In Waking Up William, use the feather on his nipples and nose until it unlocks.
  3. Deep Cleaning: In Cleaning the Floors, clean the stick figure drawing of the Vanderbooms in the top-left of the Servant's Room after cleaning the blood splatter, but before releasing the brush.
  4. A Perfect Hunt: During Going Hunting, avoid wasting bullets by shooting the pheasant, pigeon, boar shadow by the rock, boar, William on the left, William in the river, rabbit shadow by the rock, rabbit, and the deer on the left near the river.
  5. Close Inspections: During Doing the Washing, peek in the bathroom keyhole upstairs to see the masked figure.
  6. Cleaning the Windows: In Helping with Bathing, click the window and each window pane to remove the steam while Alexandra is in the bath.
  7. Garbage Disposal: At the start of Night Time Duties, go to the upstairs balcony and throw the body parts over the railing.
  8. Pest Control: In Inspecting the Cellar, take the shovel, magnet, and hammer. Use the magnet on the mousehole to get a key, click the mousehole to flush out the mouse, and hit it with the hammer.

Day 3 Achievements

  1. Petting the Cat: In Looking for the Cat, return to the Servant's Room with the cat and click it on Kate's lap multiple times until it jumps off before clicking Kate.
  2. Animal Testing: In Assisting in Alchemy, put the elixir in the parrot's water bowl.
  3. Checking the Furniture: In Unforeseen Maintenance, go to the Servant's Room and click the table leg next to the cat while it is still there to reveal a note.
  4. Seasoning the Soup: In Preparing Dinner, use the knife on the fly while making the cake, pick up the dead fly, and add it to the soup before adding the final ingredient.
  5. Finishing Touch: In Dressing Up for Dinner, click the painting of the house upstairs (third window, second row from the bottom; then the fish on the far right). Click the fish-man painting downstairs, take the pin from the jacket, and put the fish pin on William's jacket before giving him his tie.
  6. Safety Test: At the start of Serving Dinner, click the rope on the top left of the screen a few times.
  7. First Aid: In The Departure, use the fork from Aldous twice on each wound of his pulled-up trouser leg to remove bullets, then unequipped the fork and click each wound again to seal it.

How To Unlock 'You've Found Him!' (Kate's Brother Secret Location)

After finishing the game, solve seven hidden notebook puzzles across multiple chapters:

  • Clue 1 (Waking Up Aldous): Retrieve the clock hand from the soldier figurine, place it on the clock, and set it to 04:05.
  • Clue 2 (Helping With Bathing): Interact with the wall tile puzzle in this order: Alexandra, bathtub, suitcase, hand.
  • Clue 3 (Assisting In Alchemy): Input the sequence into the puzzle box: Right, Right, Right, Left, Right, Left, Right, Right, Left.
  • Clue 4 (Searching The Attic): Input symbols into the constellation box: four building icons, three water icons, two moon icons.
  • Clue 5 (Dressing Up For Dinner Wine Puzzle): Go to the cellar and match the symbol on the fifth note.
  • Clue 6 (Dressing Up For Dinner Bottle Puzzle): Align the bronze bottle over the spiral, silver bottle over the snake, and gold bottle over the triangle with a horizontal line. Open the barrel, enter the next room, and check the red cloth for the note.
  • Clue 7 (The Final Lockbox): Gather numbers from previous chapters—Helping with Bathing (6), Preparing Coffee (2), Going Hunting (9), and Assisting with Alchemy (4). Enter 6294 into the lockbox in the cellar barrel room to get the telescope.

Finally, head to the bust, take the left passage, use the telescope on the window, and pan up until the window illuminates to complete the quest.