Grumpy Old Wizards

After Horace Slughorn dies Severus Snape and a recently widowed Draco Malfoy run into potion problems. To keep Severus alive, they ask the smartest person they know for assistance. During their work Severus discovers that Lucius is up to his old tricks and is obsessed with finding out his motivations. For Golden Age Fest. Hogwarts alumni are grandparent age. SS/HG eventually.