Whilst digging in the woods botanist Liv Nash unearths the corpse of academic Murray Hawes,a man seemingly obsessed with solving the riddle of the Snark in the Lewis Carroll poem. Just before his death he had spent two hundred thousand pounds on an original copy of the poem which he felt held the key and was financing himself as a medical guinea pig to Dr Alex Falconer. Forensics show that he was killed in the Oxford Botanic Gardens and carried to the woods and amateur sleuth Michelle Marber places Falconer in the gardens at the time though he confesses to an affair with their curator,Liv's boss Helena Wright. Michelle tells Lewis she feels that Falconer and Murray's brother Conor were responsible for the death of her son Stevie. Conor founded a club for genius students and hounded Stevie to join but now Conor is the next victim after arguing with two new prospective candidates. Lewis finds that sibling rivalry,the quest for medical cures and extra-marital affairs all play a part in solving the brothers' murders.

When lonely feminist lecturer Miranda Thornton is found dead after a video she submitted to a dating agency is viciously made public on a scurrilous website,the first conclusion is suicide. But,with her answer phone removed and finger prints wiped,foul play is suspected. Miranda opposed property developer David Connelly buying land belonging to her college and had been visited,via the website by unhappily married journalist Francis Mitchell, though he states that Miranda was dead when he visited her. Embittered ex-student Sebastian Dromgoole admits to posting the video but Hathaway is guilt-ridden after Dromgoole's girlfriend,whom he had asked to find out more information,is killed. Having found themselves on the website Lewis and Hathaway find that,contrary to claims,their principal suspects have known each other for two decades.

Nick and Honey Addams return home to find their baby-sitter,Jess Lake,murdered. She was tied to a bed and indeed often posed for bondage and fetish shots for photographer Marion Hammond. She also worked in a university lab with her boyfriend Gideon's father Dr. Massey,who is divorced from his unfeeling wife Stanza. Honey admits that Nick does not have an alibi but he seems to have no link to the next victim,Jess's house mate Silas,whose corpse is also arranged in the style of one of Marion's photos. Lewis finds himself tracking a killer who is a seemingly respectable citizen but who has a split personality rendering them an obsessive.

American academic Paul Yelland faces accusations of racism when he presents his theory on Criminal Dangerousness to an Oxford college and is later found murdered. Married professors Anne and Robert Fraser claim they invited him to raise their department's profile and Robert,who is having an affair with student Nina, points Lewis towards Myra Bennett's anti-fascist group. Yelland also dealt in antiques and had angered two clients with a forgery and furthermore turned out to be the father of a staff member,whose mother he deserted when pregnant. Then Nina is killed after Anne has discovered the affair. Lewis must not only expose a killer whose motive goes back many years but battle with tooth-ache in the light of his fear of dentists.