The player Brian Clough used to call coyly 'our No 9' - his son Nigel - becomes a free agent this summer. With a number of clubs already sniffing around, Clark's first task on arriving at the City Ground at the start of his own three-year contract was to try and persuade him to spearhead Forest's effort to return to the Premier League at the first attempt.
'I spoke to Nigel for 20 minutes this morning and told him how badly I want him to stay,' Clark said. 'I tried to get across my respect for him and my ambition to go for promotion from day one. He's also got to realise the grass isn't always greener.
'It's a freedom-of-contract situation so Nigel holds all the aces, but with him I'm prepared to wait as long as it takes. I'll move heaven and earth to hold on to him.'
The 49-year-old Clark, a Forest defender under Clough Snr in the 1970s, was unexpectedly named as his replacement on Wednesday night after Martin O'Neill decided to stay with Wycombe Wanderers. Having started the day as managing director of Leyton Orient, he found himself discussing the Forest squad with his new chairman, Fred Reacher, until the early hours of the next morning.
A dozen others will soon be out of contract. Roy Keane and Stuart Pearce are not among them, but although Clark would like them to stay he did not rule out selling them.
Pearce, who missed much of last season because of injury, has two years left. Keane's deal has a get-out clause allowing him to leave after 1 October for a pounds 3.5m fee. Clark, however, may try to raise more by letting him go during the close season.
'I need assurances from Roy and Stuart that they want to play for Forest,' Clark said. 'If they show me that they don't, I'll sell them. Alan Hill (of Forest's coaching staff) read me the list of clubs who've called about Roy - it took him 20 minutes.'
He will persist with a passing game, albeit with certain amendments. Like 'scoring a few goals', he added, only half-jokingly, and getting the players fitter; training under Clough was notoriously lax. 'The players are going to get a shock,' Clark warned. 'They'll be reporting back 10 days earlier than they thought.'
There will almost certainly be new faces among them. Reacher promised a 'substantial sum' would be available to Clark, who in turn had 'certain players' in mind and noted that after 12 years' penury at Orient, spending would be a novel experience.
Talking of which, Forest had earlier introduced the newcomer at a press conference, said by a local journalist to be the first they had convened since Clough signed Trevor Francis - in 1979. Clark hoped his appointment would signal an improvement in media-club relations.
'I know the value of communication,' he told reporters, who pinched themselves that they were really hearing this on Clough's old domain. 'I've spent the last 10 years crawling on my hands and knees trying to get a line on Orient in the papers.'
During the briefing, Clark, a soft- spoken Geordie, gave an indication that he intends to be his own man. When Reacher suggested there was nothing much amiss with the squad, he interjected respectfully but firmly that they had been relegated, 'so something must have been wrong'.
Clark clearly does not blame the team behind the team. He hopes to retain Hill, Archie Gemmill and Liam O'Kane, Clough men all.
As for the legend himself, he has sworn not to interfere, but Clark would be assuring him he would 'always be welcome'. The feeling is mutual. When Reacher told Clough of their choice, he had raised both thumbs and said: 'Brilliant.'