Derrick Das Adventure is a German point'n'click game.
Good Luck!!!

Play Derrick Das Adventure

Walkthrough:
You start in your office, with your assistant Harry. Grab the sandwich from the table near the door. Try to walk out of your office and the phone rings. Answer it. Tell Harry to get the car. Walk outside.

Go to Dietmar's house. Talk to his girlfriend. Walk to the studio (door at the back). Grab the statue. Go back. Put the statue on the back of the dinosaur rug, grab the paper from its mouth and use the paper on the safe to open it. Talk to Stefania about the Beauty Saloon and Tomas Andres. Leave.

Go to your apartment. Grab the tie and hanger from your bedroom and get your ID from under the pillow.

Go to the Beauty Saloon. Grab the tube of shoe polish from the street, you'll need it later. Enter the club. Talk to the bartender to get a bottle of 80% rum. Talk to the guy in the upper right corner. Tell him you're an old friend and he'll tell you to check the airport.

Go to the airport. Steal the broom(?) from the cleaners wagon by squirting shoe polish on a couch to keep her occupied. Use the claims ticket on the wardrobe woman to get a jacket. Check the jacket to find a letter, check the letter to get the address of an industrial complex. Go there.

Use the broom to knock down the sign over the gate, to scare the dog away. Check the garbage can to find a crowbar guarded by a fat rat. Soak your sandwich in rum and drop it in. Take the crowbar. Enter the building and use the crowbar on the crate to get a chainsaw.

Now there's only one place you haven't visited, Tomas' house.

At Andres' house, walk up to the gate and then right. Use the chainsaw to get through the hedge (there is a spot that is thin enough near the left edge of the screen). Go through the gap, and you'll find yourself in the garden. Now go inside the house.

Grab the roll of gaffer tape next to the pot of paint in the centre, and the pot of paint remover from the window sill. Look at the wall left of the sink. The paint there is quite fresh. You'll need to dilute the paint remover with water from the sink; then use it on the wall, revealing a secret compartment. Open it to find a copy of Bohnen's book. Now when you go outside, you'll meet the butler in the garden. Talk to him, then head to the airport.

Here, go through all the rooms (past the cleaning lady, the tourists etc.) to the far end. You'll meet Andres. Talk to him, and he'll explain about Bohnen's tomb at the graveyard. Go there next.

You'll find his tomb at the top of the stairs. Use the crowbar to open the front part of the tomb, revealing a secret entrance.

Go down, and you'll end up in front of a huge metal door. Open the cupboard to the left, then use the coat hanger to connect the broken wires, and you'll be able to open the door using the switch.

Go in. Fix the steam pipe with the gaffer tape, then use the switch thus revealed, opening yet another secret door.

And the rest should be pretty self-explanatory.

Source: Escape the Room

Online Games point-and-click walkthrough